Pentair Amerlite 78210600 1-Inch Large Rear Hub Stainless Steel Niches for Concrete Pool and Spa Light 1-Inch rear brass hub stainless steel niches for concrete pool and spa light Sandwich gasket for vinyl Vinyl niches with chrome and brass sealing rings It includes Internal and external bonding lugs Measures 11-1/2-inch length by 8-1/2-inch height by 11-1/2-inch width