Steel pipes are connected with stainless steel pipe fittings. A pipe wrench is used to thread the pipe into a threaded fitting, taper threads are cut into the pipe's end, and sealant is applied in the form of thread-sealing compound or thread seal tape (also known as PTFE or Teflon tape). These fittings are estimated outwardly distance across the cylinder and are accessible in grades 304 or 316 pure. The fundamental structures are: Tube twists in 45 degrees, 90 degrees, 180 degrees,s and 1x Width short span 90 degrees.