NOS Corbin heater hose spring type clamps for 1953-1967 Corvettes. I purchased these 40+ years ago from Corbin before they went out of business. Corbin had the original patent from 1938. That is why they are called Corbin spring type clamps. The size code on Corbin clamps for 5/8" heater hose is A-15 and 3/4" heater hose is A-17. PH: (918)333-0748.