The GasGuard™ tamper-resistant locking valve cap helps prevent refrigerant theft, leaks, and refrigerant huffing from residential and commercial air conditioning and refrigeration equipment. The cap’s hexagonally shaped, corrosion-resistant stainless steel shell and brass core easily screws and locks onto ¼-inch or 5⁄16-inch (6.35-mm and 7.93-mm) threaded refrigerant Schrader valves. The cap restricts unauthorized access because it can only be installed or removed with a unique matching proprietary socket tool. The patent-pending GasGuard design complies with the International Mechanical Code (IMC) (Section 1101-10) and International Residential Code (Section M1411-6) requirements that mandate tamper-resistant outdoor access ports for all new air conditioning and refrigeration installations. It is available in four merchandising packaging selections: a 10, 50, or 100 pack, or in a package offering the proprietary socket tool and two free locking caps. All four merchandising packs are offered in refrigerant-identifying pink for R-410A, green for R-22, or silver for universal refrigerants. The 5⁄16-inch models are offered in only-silver 10-packs or the two-pack and tool. The 5⁄16-inch diameter sizes also are available for European and Asian a/c and refrigeration equipment. According to the manufacturer, the hexagonally shaped cap and durable polymer socket offers additional leverage for tightening by hand or with a socket extension tool.