Pex requires special fittings and a special tool to expand the tubing for it to be used
Generally barb fittings are determined by the inside diameter of the tubing. Cut a small piece and take it to the hardware store to match it up,or measure the inside diameter.There are two types of barb fittings.One is used with a hose clamp to secure it. The other has a plastic ring where the tubing attaches and requires no clamp. If you are attaching PEX tubing you should use a hose clamp to secure it as it is not as plyable as standard plastic tubing.Be careful not to over tighten the clamp.
