High Quality: The spring loading design is made of hard plastic to ensure flexibility and strength. It is rust proof and corrosion-resistant, and can be easily opened and closed when pressure is released. It is durable and has a long service life. Application: The AC line disconnection tool kit includes 7 opening sizes, 1/4 ", 5/16", 3/8 ", 1/2", 5/8 ", 3/4", and 7/8 ". Easy to See: Color-coded products provide easy identification of six sizes : 5/16", 3/8", 1/2", 5/8", 3/4" and 7/8". Suitable for many domestic and import vehicles : Ford and Chrysler air conditioning line ( spring lock couplings ) GM, Ford, and Chrysler fuel line ( quick connect couplings ) Ford radiators and transmission lines ( push lock couplings - 5/16" ) Heavy Duty: Made of a highly durable thermoplastic material that is resistant to fuels and solvents.