The adjustment knobs on transit seating hardware are handled constantly, and they are the first thing to strip or seize on a system that gets moved between a chair and a vehicle every day. This replacement knob subassembly for Therafin WC20 hardware is supplied as a pair.
New knobs restore proper clamping, which is what holds the seat position where the therapist set it. A knob that no longer bites lets the seating drift out of alignment, and that shows up as postural change long before anyone thinks to check the hardware.
Swapping them is straightforward for a technician and cheaper than dealing with the consequences of a loose mount.






