Review on Firestone Coil-Rite W237604134 Kit by Oliver Waiker

I've asked the mechanic to install them so I know they're installed correctly, he's had experience with them. They vent but they lose pressure pretty quickly not very happy not sure if the fittings are cool or it's some crappy airline but I can vent them to 30lbs and they drop to about 15lbs and in about an hour about two hours they will be flat or depressurized empty. I would really like to know what the problem is, if anyone can help me please let me know