This Centerfire neck insulator is made of rubber. It features extends life, withstands heat abuse. Plus, it is compatible with BTB, Q1515AB8BM, Q1515AB8BT, Q2015AB8CMC, Q2015AB8CTC, Q2015TB8CMC, Q2015TB8CTC, Q3015AE8ELC, Q3015AE8EMC, Q3015AE8ETC, Q3015AE8HMC, Q3015AE8XMC, Q3015TE8E and more, Bernard brand and is for use with 200/300A Bernard BTB MIG guns using Centerfire Consumables. It can be used for MIG welding.