03-86 Spring loaded block for 1" T-Track. Delrin(tm) sheave ensures smooth operation and high safe working load. Stainless Steel cheeks and Stainless Steel slider provide a strong and reliable block. Pin stop allows 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. 1-7/16" (40 mm), Max Line 7/16" (11 mm), L 3" (76 mm), W 1-1/4" (31 mm), H 3-17/32" (90 mm), Bearing Height 2-5/32" (55 mm), SWL 1000 lbs. (450 kg), Weight 4.5 oz. (128 g)