There is a handy gauge on the side of the connector to show you how far back to strip the wire. These connectors are re-useable and are great for both permanent or temporarily wiring. This 75pc kit contains the most common sizes and comes in a sturdy plastic case that can be thrown in a toolbox, bag, auto, camper, etc. Great to have for an emergency repair or just normal wiring jobs around the house or shop.
The 75pc compact splicing connector assortment contains 25x 221-412 (2 conductor), 25x 221-413 (3 conductor), 25x 221-415 (5 conductor) connectors organized in different compartments.