CNC laser cut from 1/4" thick American made mild steel for easy welding. Heavy duty design performs under the most demanding rigid frame applications. 5/16" diameter hole works perfectly with 5/16" hardware and is the proper size for you to tap to 3/8-16 if a threaded hole is needed. Save yourself a lot of time on your build by using these tabs to mount almost anything. Sold in packs of 4. Proudly made in the USA.