The machined aluminium body allows for an easy grip and the three reaming heads are controlled by a screw thread at the base.
Just twist the base until you get the desired width and then insert into your bowl and rotate. This will remove any uneven carbon build. About a 2mm build up overall is considered ideal.
Once your senior reamer is rotating freely you can increase the bore or leave it as it is.
The drill is useful for clearing anything in the stem that a pipe cleaner won't.
Keeping the carbon down ensures your pipe smokes at its optimum performance meaning you enjoy it more.