Mafell 207944 is an 3 mm reducing sleeve / adapter sleeve (German: Reduzierhülse), used on Mafell router motors so that a 3 mm shank bit or tool can be fitted in the standard 8 mm collet.
Suitable for e.g.:
Key data
Put simply: this is a small precision adapter that lets you use thinner-shank cutters in the Mafell router motor.