"SELKIRK" ADJUSTABLE ELBOW 90 DEGREE *6" *Type B gas vent *OD = ID = 1/2" *Inner wall aluminum, outerwall galvanized *For gravity draft venting of "listed" LP or natural gas burning appliances *100 million BTU per hr., 500 deg. F max. *Appropriate for thru the wall where applicable *Not for wall furnaces *UL listed *10 yr. warranty *Boxed *#6RV-EL90 *6"