Heavy duty 3/8" four pronged pound in T-nuts. These industrial grade steel T-nuts are designed with repeated use in mind and are a step up from the standard hardware store variety T-nut. Able to withstand tapping over and over again, these heavier guage steel T-nuts are the last pound in hardware you'll ever need for your home wall or gym. Simply pound these into the predrilled holes in the back of your climbing wall plywood and you're ready to go. We recommend predrilling holes at 1/2" diameter for ease of T-Nut placement