diff --git a/src/data/CCBitField.ml b/src/data/CCBitField.ml
index a7269096..574c2175 100644
--- a/src/data/CCBitField.ml
+++ b/src/data/CCBitField.ml
@@ -7,7 +7,58 @@ exception Frozen
 
 let max_width = Sys.word_size - 2
 
-module type EMPTY = sig end
+(*$R
+  let module B = CCBitField.Make(struct end) in
+  let x = B.mk_field () in
+  let y = B.mk_field () in
+  let z = B.mk_field () in
+
+  let f = B.empty |> B.set x true |> B.set y true in
+
+  assert_bool "z_false" (not (B.get z f)) ;
+
+  assert_bool "z_true" (f |> B.set z true |> B.get z);
+*)
+
+(*$R
+  let module B = CCBitField.Make(struct end) in
+  let x = B.mk_field () in
+  B.freeze();
+  assert_bool "must raise"
+    (try ignore (B.mk_field()); false with Frozen -> true);
+
+*)
+
+(*$R
+  let module B = CCBitField.Make(struct end) in
+
+  let x = B.mk_field () in
+  let y = B.mk_field () in
+  let z = B.mk_field () in
+  let u = B.mk_field () in
+  B.freeze();
+
+  let f = B.empty
+    |> B.set y true
+    |> B.set z true
+  in
+
+  assert_equal ~printer:CCInt.to_string 6 (f :> int) ;
+
+  assert_equal false (B.get x f) ;
+  assert_equal true (B.get y f) ;
+  assert_equal true (B.get z f);
+
+  let f' = B.set u true f in
+
+  assert_equal false (B.get x f') ;
+  assert_equal true (B.get y f') ;
+  assert_equal true (B.get z f');
+  assert_equal true (B.get u f');
+
+  ()
+*)
+
 
 module type S = sig
   type t = private int
@@ -17,49 +68,16 @@ module type S = sig
   val empty : t
   (** Empty bitfields (all bits 0) *)
 
-  type _ field_kind =
-    | Bool : bool field_kind
-    | Int : int field_kind
+  type field
 
-  (** Field of type [value], with a given width and position within the
-      bitfield type *)
-  module type FIELD = sig
-    type value
-    (** Values contained in the field *)
+  val get : field -> t -> bool
+  (** Get the value of this field *)
 
-    val get : t -> value
+  val set : field -> bool -> t -> t
+  (** Set the value of this field *)
 
-    val set : value -> t -> t
-
-    val width : int
-
-    val name : string
-
-    val kind : value field_kind
-  end
-
-  type 'a field = (module FIELD with type value = 'a)
-
-  val bool : ?name:string -> unit -> bool field
-  (** New field of type bool
-      @raise Frozen if [freeze ()] was called
-      @raise TooManyFields if there is no room *)
-
-  val int2 : ?name:string -> unit -> int field
-  (** New field of type 2-bits int (same as [int ~width:2])
-      @raise Frozen if [freeze ()] was called
-      @raise TooManyFields if there is no room *)
-
-  val int3 : ?name:string -> unit -> int field
-  (** New field of type 3-bits int (same as [int ~width:3])
-      @raise Frozen if [freeze ()] was called
-      @raise TooManyFields if there is no room *)
-
-  val int : ?name:string -> width:int -> unit -> int field
-  (** New field for [width] bits.
-      @raise Frozen if [freeze ()] was called
-      @raise Invalid_argument if width is not [<= 1]
-      @raise TooManyFields if there is no room *)
+  val mk_field : unit -> field
+  (** Make a new field *)
 
   val freeze : unit -> unit
   (** Prevent new fields from being added. From now on, creating
@@ -67,16 +85,9 @@ module type S = sig
 
   val total_width : unit -> int
   (** Current width of the bitfield *)
-
-  type any_field = AnyField : (module FIELD with type value = 'a) * 'a field_kind -> any_field
-
-  val iter_fields : (any_field -> unit) -> unit
-  (** Iterate on all currently present fields *)
-
-  val pp : Format.formatter -> t -> unit
-  (** Print the bitfield using the current list of fields *)
 end
 
+(* all bits from 0 to w-1 set to true *)
 let rec all_bits_ acc w =
   if w=0 then acc
   else
@@ -96,145 +107,29 @@ let get_then_incr n =
   incr n;
   x
 
-let get_then_add n offset =
-  let x = !n in
-  n := !n + offset;
-  x
-
-module Make(X : EMPTY) : S = struct
+module Make(X : sig end) : S = struct
   type t = int
 
   let empty = 0
 
-  type _ field_kind =
-    | Bool : bool field_kind
-    | Int : int field_kind
-
-  module type FIELD = sig
-    type value
-    (** Values contained in the field *)
-
-    val get : t -> value
-
-    val set : value -> t -> t
-
-    val width : int
-
-    val name : string
-
-    val kind : value field_kind
-  end
-
-  type 'a field = (module FIELD with type value = 'a)
-
-  type any_field = AnyField : (module FIELD with type value = 'a) * 'a field_kind -> any_field
-
   let width_ = ref 0
   let frozen_ = ref false
-  let fields_ = Queue.create()
-  let register_
-    : type a. (module FIELD with type value = a) -> unit
-    = fun f ->
-      if !width_ > max_width then raise TooManyFields;
-      if !frozen_ then raise Frozen;
-      let (module F) = f in
-      Queue.push (AnyField (f, F.kind)) fields_
 
-  let new_name_ () =
-    "field_" ^ string_of_int (Queue.length fields_)
+  type field = int (* a mask *)
 
-  let bool ?(name=new_name_()) () : bool field =
-    let module B = struct
-      type value = bool
-      let n = get_then_incr width_
-      let mask = 1 lsl n
-      let name = name
-      let width = 1
-      let get x = (x land mask) <> 0
-      let set b x =
-        if b then x lor mask else x land (lnot mask)
-      let kind = Bool
-    end in
-    let f = (module B : FIELD with type value = bool) in
-    register_ f;
-    f
+  let get field x = (x land field) <> 0
 
-  let int2 ?(name=new_name_()) () =
-    let module Int2 = struct
-      type value = int
-      let n = get_then_add width_ 2
-      let name = name
-      let mask = 3 lsl n
-      let kind = Int
-      let width=2
-      let get x = (x land mask) lsr n
-      let set v x =
-        assert (x >= 0 && x < 4);
-        let x = x land (lnot mask) in
-        x lor (v lsl n)
-    end in
-    let f = (module Int2 : FIELD with type value = int) in
-    register_ f;
-    f
+  let set field b x =
+    if b then x lor field else x land (lnot field)
 
-
-  let int3 ?(name=new_name_()) () =
-    let module Int3 = struct
-      type value = int
-      let name = name
-      let n = get_then_add width_ 3
-      let mask = 7 lsl n
-      let width = 3
-      let kind = Int
-      let get x = (x land mask) lsr n
-      let set v x =
-      assert (x >= 0 && x < 8);
-      let x = x land (lnot mask) in
-      x lor (v lsl n)
-    end in
-    let f = (module Int3 : FIELD with type value = int) in
-    register_ f;
-    f
-
-  let int ?(name=new_name_()) ~width:w () =
-    let module F = struct
-      type value = int
-      let n = get_then_add width_ w
-      let mask_unshifted = all_bits_ 0 w
-      let mask = mask_unshifted lsl n
-      let kind = Int
-      let name = name
-      let width = w
-      let get x = (x land mask) lsr n
-      let set v x =
-      assert (x >= 0 && x <= mask_unshifted);
-      let x = x land (lnot mask) in
-      x lor (v lsl n)
-    end in
-    let f = (module F : FIELD with type value = int) in
-    register_ f;
-    f
+  let mk_field () =
+    if !frozen_ then raise Frozen;
+    let n = get_then_incr width_ in
+    if n > max_width then raise TooManyFields;
+    let mask = 1 lsl n in
+    mask
 
   let freeze () = frozen_ := true
 
   let total_width () = !width_
-
-  let iter_fields f = Queue.iter f fields_
-
-  let pp out x =
-    let ppf = Format.fprintf in
-    ppf out "{@[<hv>";
-    let first=ref true in
-    Queue.iter
-      (fun (AnyField ((module F), kind)) ->
-        if !first then first := false else ppf out ",@ ";
-        match kind with
-        | Bool ->
-            let b = F.get x in
-            ppf out "%s=%b" F.name b
-        | Int ->
-            let i = F.get x in
-            ppf out "%s=%u" F.name i
-      ) fields_;
-    ppf out "@]}"
 end
diff --git a/src/data/CCBitField.mli b/src/data/CCBitField.mli
index 5e43f47d..adf37439 100644
--- a/src/data/CCBitField.mli
+++ b/src/data/CCBitField.mli
@@ -6,28 +6,22 @@
   up to 30 or 62 bits (depending on the architecture) in
   a relatively type-safe way.
 
-{[
-module B = CCBitField.Make(struct end);;
+    {[
+      module B = CCBitField.Make(struct end);;
 
-#install_printer B.pp;;
+      #install_printer B.pp;;
 
-module X = (val B.int ~name:"x" ~width:3 ());;
-module Y = (val B.int ~name:"y" ~width:2 ());;
-module Z = (val B.bool ~name:"z" ());;
+      let x = B.mk_field ()
+      let y = B.mk_field ()
+      let z = B.mk_field ()
 
-let f = B.empty |> X.set 3 |> Y.set 1;;
+      let f = B.empty |> B.set x true |> B.set y true;;
 
-Z.get f ;;
+      assert (not (B.get z f)) ;;
 
-f |> Z.set true |> Z.get ;;
+      assert (f |> B.set z true |> B.get z);;
 
-Format.printf "f: %a@." B.pp f;;
-
-]}
-
-{b status: experimental}
-
-@since 0.13
+    ]}
 *)
 
 exception TooManyFields
@@ -36,9 +30,6 @@ exception TooManyFields
 exception Frozen
 (** Raised when a frozen bitfield is modified *)
 
-module type EMPTY = sig end
-(** Used for generativity on versions of OCaml older than 4.02 *)
-
 val max_width : int
 (** System-dependent maximum width for a bitfield, typically 30 or 62 *)
 
@@ -51,49 +42,16 @@ module type S = sig
   val empty : t
   (** Empty bitfields (all bits 0) *)
 
-  type _ field_kind =
-    | Bool : bool field_kind
-    | Int : int field_kind
+  type field
 
-  (** Field of type [value], with a given width and position within the
-      bitfield type *)
-  module type FIELD = sig
-    type value
-    (** Values contained in the field *)
+  val get : field -> t -> bool
+  (** Get the value of this field *)
 
-    val get : t -> value
+  val set : field -> bool -> t -> t
+  (** Set the value of this field *)
 
-    val set : value -> t -> t
-
-    val width : int
-
-    val name : string
-
-    val kind : value field_kind
-  end
-
-  type 'a field = (module FIELD with type value = 'a)
-
-  val bool : ?name:string -> unit -> bool field
-  (** New field of type bool
-      @raise Frozen if [freeze ()] was called
-      @raise TooManyFields if there is no room *)
-
-  val int2 : ?name:string -> unit -> int field
-  (** New field of type 2-bits int (same as [int ~width:2])
-      @raise Frozen if [freeze ()] was called
-      @raise TooManyFields if there is no room *)
-
-  val int3 : ?name:string -> unit -> int field
-  (** New field of type 3-bits int (same as [int ~width:3])
-      @raise Frozen if [freeze ()] was called
-      @raise TooManyFields if there is no room *)
-
-  val int : ?name:string -> width:int -> unit -> int field
-  (** New field for [width] bits.
-      @raise Frozen if [freeze ()] was called
-      @raise Invalid_argument if width is not [<= 1]
-      @raise TooManyFields if there is no room *)
+  val mk_field : unit -> field
+  (** Make a new field *)
 
   val freeze : unit -> unit
   (** Prevent new fields from being added. From now on, creating
@@ -101,55 +59,11 @@ module type S = sig
 
   val total_width : unit -> int
   (** Current width of the bitfield *)
-
-  type any_field = AnyField : (module FIELD with type value = 'a) * 'a field_kind -> any_field
-
-  val iter_fields : (any_field -> unit) -> unit
-  (** Iterate on all currently present fields *)
-
-  val pp : Format.formatter -> t -> unit
-  (** Print the bitfield using the current list of fields *)
 end
 
 (** Create a new bitfield type *)
-module Make(X : EMPTY) : S
-
-(*$R
-  let module B = CCBitField.Make(struct end) in
-
-  let module X = (val B.bool ()) in
-  let module Y = (val B.int2 ()) in
-  let module Z = (val B.bool ()) in
-  let module U = (val B.int ~width:4 ()) in
-
-  assert_equal 2 Y.width ;
-  assert_equal 4 U.width ;
-
-  let f = B.empty
-  |> Y.set 3
-  |> Z.set true
-  in
-
-  assert_equal 14 (f :> int) ;
-
-  assert_equal false (X.get f) ;
-  assert_equal 3 (Y.get f) ;
-  assert_equal true (Z.get f);
-
-  let f' = U.set 13 f in
-
-  assert_equal false (X.get f') ;
-  assert_equal 3 (Y.get f') ;
-  assert_equal true (Z.get f');
-  assert_equal 13 (U.get f');
-
-  ()
-*)
-
+module Make(X : sig end) : S
 
 (**/**)
-
 val all_bits_ : int -> int -> int
-(** Undocumented, do not use. Exposed for testing purpose *)
-
 (**/**)