I’ve just finished a little interbreeding with a Hase Kettwiesel and an ICE head-rest. The client is someone who loves her Kettwiesel, and it has enabled her to come back on a bike due to a bad back. She then started having problems with an old neck issue.
To help this problem, her requirements were to fit a neat padded support in the small of her neck, under her helmet (the wearing of which, is mandatory in Australia). As the stock Hase Kettwiesel head-rest was a no go and the cross bar on the seat too large for most other options, I bolted a tube @ 45 degrees up to clear the panier bags with 110mm x 8mm brooker rod.
The ICE head-rest worked perfectly along with the CATRIKE tie rod as a spacer.