Salmon River Solutions Srs Trinity Rail Black. With a radius cut and outer flats on the bottom it will match well to a rounded or flat bottom stock. With 1.7'' of arca a Spartan Precision quick release adaptor and 2'' of usable picatinny this is the most universal rifle mount ever created. Flexible bolt spacing of 1.5'' to 3.5''. Specifications for Salmon River Solutions SRS Trinity Rail: Manufacturer: Salmon River Solutions Color: Black Finish: Anodized Fabric/Material: 7075 Aluminum Gun Rail: Arca Picatinny Gun Type: Rifle Features of Salmon River Solutions SRS Trinity Rail Arca Picatinny Spartan Package Contents: Salmon River Solutions SRS Trinity Rail M-Lok Fasteners 10-32 Fasteners Salmon River Solutions 1122: Srs Trinity Rail Black