Easy to use. They come in different ranges and fitting sizes so make sure you get one that is within the range you need and has a fitting that will fit on any existing sockets. Normally dialed in at the bottom, they click when the correct torque is set and "break" if you try and over tighten. Remember to wind out the wrench after use to maintain it's accuracy (loosen the adjuster at the bottom). Normally come with a guide to convert different measurements so between pound feet, newton metres etc.