This cover fits the first check of the 3/4 - 1" Watts 909 & 909-HW series backflow preventers. No special tools are required for servicing. Made of high quality lead free bronze, will fit original 909 models and lead free 909 models. This cover is tapped to recieve a test cock. Thread tap size is 1/8" NPT. Test cock sold seperately. Genuine Watts replacement parts.