supply of industrial safety helmet and h/l voltage , industrial safety helmet and h/l voltage approach electric alarm. technical parameters: pow er supply: 2 nos. cr1632(140 mah) button cells included, alarm range: 1 kv-500 kv(high voltage alarm), w orking frequency: 50hz/60hz, electricity testing mode: non-contact mode, detection mode: automatic trig ger, alarm distance error: +/- 10 cm (under base condition), dimension : 88mm x 32mm x3mm, alarm mo de: indicator- led light visibility under 8000 lx visible, buzzer- above 60db(form 60 cms distance), protecti on level: ip54.make: metravi/bosch / fluke or similar [ warranty period: 30 months after the date of deliv ery ] ]