7 Series blocks offer medium sized racing and cruising yachts Delrin and Delrin ball bearing sheave blocks with some of the highest performance statistics. They are true workhorse blocks and will provide years of trouble-free service. Highly polished stainless steel blocks are reinforced with large, stainless V-straps and head posts All blocks have universal adapters with three-way head design for free swiveling or front/side set poistions Sheave diameter: 2-3/8" Pin diameter: 1/4" SWL: 2,250 lbs.; ball bearing: 1,700 lbs.