These repair kits are very popular with experimentalists and kit builders as an economical alternative to serrated inserts. They contain everything you'll need to make on-the-spot engine repairs. Includes piloted tap, and installation tool, and 30 inserts with the following reaches: 3/8" (6), 7/16"(6), 1/2"(6), 3/4"(6) and .472"(6). Note that the use of non-aviation Heli-coil inserts may not be approved for your engine. Check with the manufacturer before using. 3 lbs (1.5Kg) shipping weight.