Bastion Laser Engraved Rear Cover Slide Back Plate For Glock 17 19 21 22 23 24 26 27 29 30 31 32 33 34 35 36 37 38 39 40 41 Gen 1-4 Butt plate, Does not fit Glock 42 & 43 Models - Cross Compatible with Glock 17 19 21 22 23 24 26 27 29 30 31 32 33 34 35 36 37 38 39 40 41 Models Gen 1-4 ONLY. NOT COMPATIBLE WITH MODELS G42 OR G43. Not compatible with Gen 5 Hard coat anodized black T6 machined aluminum Lasered artwork won't rub off; not painted Replaces plastic factory part Black anodized aluminum; not plastic