The ZSC98A is compact stop clock specifically designed for use in schools. At 9.5cm x 9cm x 7.5cm 15 can fit in a single Gratnells tray saving space in your lab. The ZSC98A is specifically designed for use in schools. The highly accurate quartz stop clock is housed in a robust ABS casing. The unit can be used with remote switches, timing gates etc. via the 4mm sockets which are located at the rear of the housing, to keep wires neatly away from the work area in front of the timer.