Stand up spring block for 1" T-Track. Delrin(tm) sheave ensures smooth operation and high safe working load. Stainless Steel cheeks and stainless steel slider ensure reliability. Polyethylene liner and pin stop allow for easy adjustment. Track Size 1" x 1/8" (25 mm x 3 mm), Boat Size Up To LOA, Displ., Sail Area: 27', 5000 lbs., 315 sq. ft (8 m, 2270 kg, 29 m2), Sheave Dia 2" (51 mm), Max Line 7/16" (11 mm), Length 3" (76 mm), W 1-1/4" (31 mm), H 4-5/32" (105 mm), Bearing Height 2-7/32" (56 mm), SWL 1750 lbs. (795 kg), Weight 6.5 oz. (184 g)