PrimoChill Tool Free Ghost Fitting Industry Standard G 1/4" Threads, Barb Size - 1/2 OD for 1/2 ID Tubing - 2 Pack, Nickel Plated Brass Shortened thread portion of the fittings to better suit CPU and GPU block depthsimproving flow. Removed unneeded wrench flats all together in favor of a much more user friendly tool free knurling. Knurling is Gnarly =) O-ring shoulder made with appropriate thicknessas in thinner. Makes for a shorter fitting overall without sacrificing needed length in the barrel portion. Tool Free Design* Specifications: * Material - Nickel Plated Brass * Thread Size - G 1/4 * Barb Size - 1/2 OD for 1/2 ID Tubing * Inside Bore Size - .40 * Overall Length - .940 * O-ring Material - Buna 70 * ROHS Compliant - Yes