Read about Shark Bites here on Mud, saved me some time and work. There's a little side load on the fitting, not ideal, but it's not leaking. No instructions came with the fitting, but I checked the manufacture's website Elkhart Products Corporation and saw I needed to use the tube liner with PEX. That restricts the flow some, but it looks like no smaller ID than the frost-free faucet I was replacing. I had to cut the PEX off the old faucet, bought a longer faucet to make up the missing length.