This is a Pentair 78232401 Large Standard 10-Hole Pattern Light Niche for Vinyl and Fiberglass Installation in Canada. It has a 3/4 inch rear hub and stainless steel housing. This light niche meets CSA standards for Canada. This niche includes sandwich gasket for vinyl liner pools.
This Pentair light niche is for a Fiberglass/Vinyl Liner swimming pool. Measurements are 12-1/2 inch diameter and a 8.02 inch depth.
