Underdome bell housed in white cabinet for added resonance. Loud ringing sounds (80db at 1m) suitable for both comercial and domestic applications. Typlical battery life – 4 years (alkaline). Battery power means that you only require a wire from the push to the bell, Requires 2 x R20/D batteries NL183N, Bell can be located up to 9m from push, 5 years guarantee.