PrimoChill Tool Free Ghost Fitting Industry Standard G 1/4" Threads, Barb Size - 3/8 OD for 3/8 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* Ghost Design**