Model 3: For Remington Model 4, 74 and 7400. Model 14: For Ruger Mini-30 and Mini-14 standard and ranch rifles except series 180 and Ruger folding stock. Quick detachable. Weight: 3 oz. Model 4: Universal Adapter - Requires two inches of uncluttered barrel for mounting. Fit barrels from.550 diameter to.812. Model 5: Fits AR-15 Round Handguard. Sling Swivel included. Model 6: For European size rails (about 3/8" across rail slot.). Model 6A: For rails about 5/16" across slot.