A punch down tool, also called a punchdown tool is a small hand tool used by telecommunication and network technicians. It is used for inserting wire into insulation-displacement connectors on punch down blocks, patch panels, keystone modules, and surface mount boxes (also known as biscuit jacks).

This punch down tools is 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, and then the punch down tool is pressed down on top of the wire, over the post. Once the required pressure is reached, the internal spring is triggered, and the blade pushes the wire into the slot, cutting the insulation, and securing the wire. For light-duty use, there are also less expensive punch down tools with fixed blades and no impact mechanism.

The "110" type punch-down tool is suitable for all network racks, CAT5E and CAT6 keystone or network connections. The 110 block is often used at both ends of Category 5 cable runs through buildings. In switch rooms, 110 blocks are often built into the back of patch panels to terminate cable runs. At the other end, 110 connections may be used with keystone modules that are attached wall plates. 110 blocks are preferred over 66 blocks in high-speed networks because they introduce less crosstalk and many are certified for use in Category 5 and Category 6 wiring systems, even Category 6a.