Tier One Picatinny to ARCA Adapter - Short Black. Ideal for rifles with in-built Arca rails. Short version for rimfire or slim rifle stocks. Extended version also available for higher caliber rifles. Specifications for Tier One Picatinny to ARCA Adapter: Manufacturer: Tier One Color: Black Fabric/Material: Aluminum Package Contents: Tier One Picatinny to ARCA Adapter Nil Tier One T1ARCA-010: Picatinny to ARCA Adapter - Short Black