Extra metal in the two mounting surfaces (hex and round) for more secure fit
Hex on one side, round on other (may use either side) one inventory for all props
Zinc plated and coated with gold chromate for double protection
Set screws are heat treated, black oxide
Mounting screws: zinc plated ,heat treated, pan slotted - with locking serrations under the head - with nylock patch for added locking strength (double locking device designed to grip into the threads without backing out)
All Steal; 5/8 has Keyway HEX/ROUND HUBS - with screws
Plumbing, Electrical & HVAC Distributor
