Macro line hose is used on many paintball system, connection the valve or regulator to the ASA (where the bottle attaches). This hose is black and is priced per foot. If you buy multiple feet, it will be in pre-cut one foot lengths. Macro line can be cut with a mat knife. Connection fittings are both straight and 90 degree swivels. It is also possible to get metric fitting for the few rare guns that need it. (Tippmann markers use standard fittings.)