Evolution Gun Works Chamber Checker 20 Gauge. 45 Long Colt with one easy to use checker. The Evolution Gun Works Cowboy Chamber Checker and has an anodized matte black finish for amazing durability. The Cowboy Chamber Checker uses the actual Clymer reamers that are used to chamber barrels. Specifications for Evolution Gun Works Chamber Checker: Manufacturer: Evolution Gun Works Quantity: 1 Color: Black Condition: New Fabric/Material: 6061-T6 Aluminum Finish: Matte Features of Evolution Gun Works Chamber Checker: Machined from solid 6061 T6 aircraft grade aluminum. Check 357 44-40 44 Mag and .45 Long Colt with one checker. EGW uses the actual Clymer reamers that are used to chamber barrels. Anodized matte black for durability. Package Contents: Evolution Gun Works Chamber Checker Evolution Gun Works 70196: 20 Gauge Chamber Checker