Electronic Ignition Module (Coil). M-Tronic Starting from the serial number: 1 81 222 948 The MS 441 C-M chainsaw starting from serial number 1 81 222 948 has a new carburettor and a new control unit. The idling speed of the chainsaw is more stable. The new carburetor must be mounted in combination with the new control unit. In order for the new carburetor to also be used in previous version chainsaws, it must be mounted in combination with the new control unit. The idling speed of the chainsaw is more stable. The software of the new ECU has been modified for the new carburetor. The STH/11384004701 control unit for previous version chainsaws is no longer available. The new control unit STH/11384004707 cannot be used for previous version chainsaws. The new control unit must be mounted in combination with the new carburettor. If a previous control unit needs to be replaced, use the new control unit/carburettor set STH/11380071008. Models: MS 441 C-M MS 441 C-M RVWZ MS 441 C-M RZ MS 441 C-M VWZ MS 441 C-M W MS 441 C-M Z MS 441 C-MQ MS 441 C-MQ Z