Patent # 6,126,122;Clamps ¼" - 1" CTS tube (copper, PEX or CPVC) and 1/8" - 1" Sch. 40 pipe (steel or plastic);Releasable locking mechanism allows for variable clamping tension for expansion and contraction;Provides ¼" stand-off from mounting surface;PlenumSafe model meets ASTM E84 25/50 Flame/Smoke Spread and UL-94 V0 flame ratings