These brushes are sized to fit fittings that accept 1/2 ID copper tubing. While they work well, they're a little weaker than most brushes I've used in my 45 years as a locksmith. Since they're a little looser than most, I believe they'll fit 1/2 OD tube fittings for you AC folks. Because of the price I bought them to cut off the grips and put them in my drill press to remove rust in hard to reach spots on the engine block.