Sea-Dog, aka Sea-Lect Designs part number K199200. Almost identical to the Hobie Seat Strap Hook (part number 81267001). Best used as a replacement seat strap part. Use with one inch webbing strap, secure with a one inch tri-glide. Spring loaded snap hook for ocean going kayak seats. Sea-Lect part number K199200.

This is a generic part is nearly identical the Hobie part but does NOT bear the Hobie logo as shown.
A = 1/2 inch, B = 1 1/32 inches, C = 1/8 inch.

Other similar strap and hook parts:
Hobie 72021005 Live-well Strap; Use this hook, one inch web strap, a one inch buckle and triglide.
Hobie 81259001 Seat Strap With Hook; Use this hook, one inch webbing strap, and a one inch tri-glide.
Hobie 72409001 Seat Strap and Hook; Use this hook, one inch webbing strap, a super lock, and 2 one inch tri-glides.