The Commander Rotary Alarm Bell sounds a 60db alarm with a range of 35 metres, making it as reliable and effective as its automatic or electric counterparts. The alarm also features a pre-drilled base plate which enables it to be installed quickly and easily. This rotary hand bell provides a very simple and easy to use temporary alarm system. The dome is simply turned making it hit a metal clanger inside which creates a loud, fast ringing sound. They are ideal for building sites and caravan sites. 60db alarm with 35m range Red die-cast aluminium dome and aluminium base Pre-drilled flange Maintenance free Robust design