Trac Outdoors Oar Locks - Safely Secures Your Oars - Fits Oar Shafts Up to 1-7/8-inches - 2 Pack (50428) , Black , Standard Black Chromate surface finish over zinc-plated steel adds an extra layer of corrosion protection.Fit Type: Universal Fit Fastens securely to oars with adjustable bolts 2" straight shaft Shank Diameter: 1/2"