BX120-V4 was developed on the basis of the first BX100 model. It was equipped with Nicasil-coated cylinders and a modified body, and has become a flagship for scale and tow models with a take-off weight of up to 23kg. The BX120-V4 engines impress through their top starting and running characteristics. This drive unit can be optionally equipped with a silencer. This version is advertised as a “whisper drive”. The smallest flat engine can be supplied with or without an electric starter. The add-on parts are red. They can also be ordered in black or blue.