Material: polypropylene with 13 steel spikes that are 1.2 inches in length. Using a nylon lock nut, the nylon ring will deform after locking, filling the gap between 
the connectors at both ends, so as to play a locking role.
Universal size: Epoxy spike shoe is 11.8*5.1 inch + 13 corrosion-resistant steel spikes composition. 
Easy to install and remove.