For use on 5/8" diameter Catalina 34 and Catalina 36 turnbuckle T-bolts and toggles. Typically used where the forestay turnbuckle attaches to the stem fitting, or the backstay turnbuckle attaches to the backstay chainplate.

Also used for connecting the upper shrouds to the shroud tangs for the C-34 and C-36 with the traditional non-furling masts.