Abstract: The present invention relates to a binder comprising a cover made up of two lateral parts; at least one pair of rails; said rails extending parallel to the sides of the lateral parts and at the inside thereof; and a metal ring mechanism located upon said cover, which mechanism is provided at each side with at least one built in projection (herein: “a removable and/or replaceable metal ring mechanism”); said built in projections to be inserted into corresponding rails. Moreover, the invention relates to a removable and/or replaceable metal ring mechanism, which mechanism is provided at each side with at least one built in projection.