These connectors are unique. They allow you to "T" off of an existing wire by crimping the wrap-around female spade connector (self-insulating, no taping or soldering required) and then plugging in your new wire, with included male spade connector. This is a great way to add connections for accessory automotive lighting, trailer wiring, etc. Included are 40 sets of each size wire, ranging from 10ga to 22ga, for a total of 120 sets (240 pieces), organized in a nice clear plastic box. These will come in very handy.