ATF is issuing this open letter to assist the firearms industry and the public in understanding whether a “partially complete, disassembled, or nonfunctional” frame of a Polymer80, Lone Wolf, or similar semiautomatic, striker-fired pistol (sometimes generally referred to as “Glock-type” pistols) has reached a stage of manufacture such that it “may readily be completed, assembled, restored, or otherwise converted” to a functional frame, and is therefore classified as a “frame” or “firearm” in accordance with the final rule titled Definition of ‘Frame or Receiver’ and Identification of Firearms (Final Rule 2021R-05F).