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).
Most punch down tools are of the impact type, consisting of a handle, an internal spring mechanism, and a removable slotted blade.
For light-duty use, there are also less-expensive punch down tools with fixed blades and no impact mechanism.
To accommodate different connector types, 66, 110, BIX and krone blocks require different blades.
[2] Krone blades require a separate scissor-like mechanism for trimming the wire.