4 Type L Pellet Pipe Wall Thimble from the VP Collection. This wall thimble is used for installation through a combustible wall. It maintains airspace clearance with combustibles and centers the pipe between the walls. It s telescopic design can be used on standard walls 5 to 9 thick. The VP Collection features proven coupling joint connects in seconds to assure joint integrity, gasketed joint design, painted pipe lengths available for interior use. The rolled-over male end eliminates sharp edges, and internal spacing bead assures uniform insulating air space between pipe walls. VP pellet pipe works for pellet or corn burning stoves approved for use with PL-Vent. The appliance's flue gases must not exceed 570-F and the pipe is UL Listed to ULC S609, ULC ORD C441 and UL 641. Gasketed joint designInternal spacing bead assures uniform insulating airspace.Clearance: 1 to combustibles Fuels: Pellet, Corn Materials: Inner wall 304 stainless steel and outer wall paintable galvanized Temperature: 570 degrees F UL Listed: UL641