Most punch down tools are of the impact type, consisting of a handle, an internal spring mechanism, and a removable slotted blade. To use the punch down tool, a wire is pre-positioned into a slotted post on a punch block, and then the punch down tool is pressed down on top of the wire, over the post. Once the required pressure is reached, an internal spring is triggered, and the blade pushes the wire into the slot, simultaneously cutting the insulation and securing the wire.

The tool blade does not cut through the wire insulation to make contact, but rather the sharp edges of the slot in the contact post itself slice through the insulation. However, the punch down tool blade also is usually used to cut off excess wire, in the same operation as making the connection; this is done with a sharp edge of the punch down tool blade trapping the wire to be cut against the plastic punch block. If this cutoff feature is heavily used, the tool blade must be resharpened or replaced from time to time.