Type 316 Stainless Steel Here’s a real time and money-saver. The Invisiware® Threaded Tab screws into a drilled and tapped hole on the inside wall of the end post. You save the expense of welding tees or tabs onto your end post, for mounting Adjust-A-Jaw® or Adjust-A-Body™ Tensioners or Ultra-tec® Fixed Jaws. Recommended only when you are using a minimum schedule 80 pipe end post or a square or rectangular steel end post with a minimum .250" wall