Barb Dia.(Fit Hose ID): 8mm to 6mm((5 or 16" to 1 or 4") Total Length: 44mm or 1.73" Hex Width: 10mm or 0.39" Barb Length(Approx): 17mm or 0.67" The coupling for connecting two hoses with the different diameter in a straight run. The barbed stems create a tight seal on flexible and semi-rigid hose when used with a hose clamp or crimp sleeve or ferrule (not included). Brass for corrosion resistance, ductility at high temperatures, and low magnetic permeability Commonly used to connect lines for air, water, fuel, oil and inert gases in a quick and simple way. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-YJL official store