These speed loaders by SGMT are excellent to making loading your factory or aftermarket Glock magazines easier and faster. Made of Durable Glock Polymer. Compatible with 9mm .40 .357 .380 and .45 GAP Factory and aftermarket Glock magazines. - Works with Magazines for the following Glock pistols: G17 G19 G22G23G26G28G31G32G34G35G37G38G39 - NOTE: NOT for use on the G42 single stack magazines G43 Single Stack 9mm or 10mm Magazines and Glock .45 Auto