A tap handle is an attachment that connects to a tap faucet and is pulled to open or close the faucet. While tap handle is the most common term for the attachment it may also be called a pull, knob, ball, or it may be abbreviated to just a handle or tap (for the standard meaning of tap refer to Beer Taps).
The tap handle may be attached to the tap in multiple different ways. The most common way is with a threaded attachment, this is the most common and if the handle is flush with the tap it’s likely to be threaded. With Guinness and some other nitrogen-based tap systems, the attachment may be a rod and pin-based system. While it’s rare there are some taps that have a fixed handle, you normally won’t see this in bar systems but it’s common for portable tap systems as well as barrel taps.
Tap handles are made out of many different materials such as wood, lucite, metal, plastic, and ceramic. Many times the type of material depends on when the handle was made and what company produced it.
A tap handle has multiple parts and the complexity will depend on the design and manufacturer. For a basic tap handle you may just have a thread adaper and the main handle while more complex taps will have a ferrule, threaded rod insert, multiple handle components, and a final.