Amazon has WiHa 1/4″ bit adapter for $6.96. Works with the stubby that was posted last week. This is the cheapest price since march.
Disclosure: We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites. All affiliate links earn me credit or a commission. it won’t cost you any extra but will help me.