The rapid rising/falling sound used on modern Police, Fire, Ambulance and other emergency services vehicles. New dual-rate version; can be switched from slow to fast siren with extra switch, if desired (P43/44 is ideal). Rate, tone frequency and volume are fully adjustable, with 1 Watt output capability. For operation on 6 to 12 Volts. Size 71mm x 49.5mm x 23mm.