8'' DuraBlack Stainless Steel Tee w/Clean-Out Cap 8'' DuraBlack Stainless Steel Tee w/Clean-Out Cap is used for a single-wall connector pipe on a rear exhaust appliance. Requires 18" clearance to combustibles. 430 series Stainless Steel with a high polish reflective finish. Subtract 1 1/4" from the overall length measurement to calculate the installed length.