PROXXON 28941 three-jaw rotary chuck
Proxxon 28941 accepts 0.3 to 3.2 mm shanks on compatible tools.

How to choose
Choose by tool model before relying on the diameter range. Proxxon publishes model exceptions that matter even if the bit shank falls within the chuck’s range.
Compatibility and limits
0.3- to 3.2-mm shank range on approved tools · verify MICROMOT model
Questions before buying
Can I fit the 28941 to an IBS/E because the diameter range matches?
Proxxon lists the IBS/E as an exception for this chuck. Check the approved holder in the specific tool documentation. The accessory shank range applies after tool-side fit is established.