The ZM18 series comprises four models with a well defined set of functionality. The base model B is characterised by its simplicity. It features an on/off control, but without intensity adjustment or triggering. The standard S3 model provides intensity adjustment using an analog modulation and fast switching of up to 500 kHz frequency (digital TTL trigger). This allows adjustment of the intensity and switching the laser at short intervals. The high-end H3 model is based on the S3 (TTL frequency limited to 100 kHz). In addition, it features internal monitoring and storage of operating parameters (temperature, run time) for fault detection and lifetime prediction purposes. The DM53 is an additional model particularly developed for low power applications with space restrictions. It is based on the B mode, additionally equipped with a TTL input line (100 kHz), that runs on 4-6 V. It's housing has been optimized to the shortest possible form factor.