SSK Firearms Interlock Safety Contender 894 Black Oxide. MUST BE HAND FIT BY A QUALIFIED GUNSMITH. Specifications for SSK Firearms Contender Interlock Safety: Manufacturer: SSK Firearms Color: Black Finish: Oxide Gun Make: Thompson/Center Arms Gun Model: Thompson/Center Contender Fabric/Material: AISI4140 Package Contents: SSK Firearms Contender Interlock Safety What firearm models does the manufacturer say SSK Firearms Contender Interlock Safety is compatible with? The manufacturer suggests that SSK Firearms Contender Interlock Safety is compatible with Thompson/Center ContenderSSK Firearms CRC894: Interlock Safety Contender 894 Black Oxide