These layshafts for performance engine/gearboxes as the standard type would flex and resullt in the breakage of the bearings causing seizure. Produced in an upgraded material EN36 and heat treated to the correct core depth they are a must in any straight cut gearbox or helical type where the engine has been tuned. For 3 synchromesh mini gearboxes only and although 2 lengths were fitted this is universal for all cases.