Salmon River Solutions SRS Arca Mini Rail Black. Made from 7075 aluminum we were able to design an incredibly light but tough rail at only .55 oz. These work in Arca Swiss style tripod heads. They are 1.7 OAL and has a slot for bolt spacing up to 1.2''. Specifications for Salmon River Solutions SRS Arca Mini Rail: Manufacturer: Salmon River Solutions Color: Black Finish: Anodized Fabric/Material: 7075 Aluminum Gun Rail: Arca Gun Type: Rifle Features of Salmon River Solutions SRS Arca Mini Rail Arca Package Contents: Salmon River Solutions SRS Arca Mini Rail M-Lok Fasteners 10-32 Fasteners Salmon River Solutions 1115: SRS Arca Mini Rail Black