Type 57IL has a proprietary design where the 316 stainless steel lugs are inserted into the valve body during the injection-molding process, permanently combining the lugs and valve body into one unit. The design permits removal of the downstream flange while maintaining full upstream line pressure. Encapsulating the 316 stainless steel lugs in the PVC valve body ensures that every valve is factory-equipped with lugs. The flange stopper employs absorption channel technology so it is nearly impossible to affect the performance of the butterfly valve by overtightening the mating flanges.
Asahi/America Inc., (800) 343-3618