CURT 81437 5/16 In Clevis Grab Hook Grade 70 4700 Lb Capacity Designed for use on transport binder safety chain to tie down heavy cargo and can also be used to connect safety chains from trailer to tow vehicle Rated for 4,700 lbs. work load limit and meets requirements for high-test chain (each hook must meet or exceed gross trailer weight) Hook pin and cotter pin provide an easy, secure attachment to safety chain 5/16" diameter Constructed from high-strength, heat-treated steel and protected by a durable yellow zinc-plated finish (grade-70 rating)