This looks pretty much like the first mountain bike I had somewhen late 80s early 90s. Kettler Aluminum Rad | Vintage mountain bike, Mountain biking, Bike
QUADRIGA P5 BELT FL | KETTLER Alu-Rad
1990's aluminium MTB frame set Kettler ALU RAD Adventure XR made in Germany YST | eBay
retro Kettler mtb | Flickr
2020 Kettler Escaro Pro Touring & Country - Walkaround - 2019 Eurobike - YouTube
KETTLER QUADRIGA TOWN & COUNTRY COMP C2 review | E-MOUNTAINBIKE Magazine