SharkBitePlumbing.com is your source for SharkBite fittings, gauges, valves and more..Repair fittings for Polybutylene tubing. Q. “I purchased some ” and ” pipe, but I’m not sure how loose or they should be..Information. SharkBite’s Polybutylene Conversion Coupling is the easiest way to transition your Polybutylene water line to a different type of pipe..Polybutylene is a plastic resin used in the manufacture of plastic pipes and fittings from . During this time polybutylene was installed in up to ten million homes and businesses throughout the United States including Atlanta..