The RT21X thumb throttle uses sx49e 520 hall sensor.
If the 108x uses the same (not opened mine up) then you can get similar for £2 - £4 with ss49e designation.
Boardman cx/mx (1) Oxydrive kit(270rpm ). (2) Bafang cst & KT kit (270rpm), (3) Q128C & KT kit( 201 rpm)), (4) Yose CST & KT kit (270rpm).
2 x Swizzbee 50c.(24V Heinzman brushed motor).
Kona Blast BBS01 with failed bbs01.
Pinnacle Arkose 2 with Revos friction drive ,2 x 8.7ah 24v batteries.
Cotic Roadrat built up from scratch. Bafang G370 front hub in steel surly forks and rear alfine 8 hub gears.
Kona Ute cargo bike conversion with TDZs2 & 32/42t double. Massive cargo lugging ability and the addition of a Carryfreedom with 1m x 600mm flat bed.