VESSEL SDL-01 static test instrument for measuring the charged object. Its ultra-small, super cheap price, can be a simple static measurements: 
 Model 
 SDL-01 
 That range 
 0 ~ ± 19.9KV (the smallest unit that 0.1KV) 
 Detection range 
 50mm (between the body and detect objects) 
 Power supply voltage 
 DC6V (3 alkaline batteries) 
 Direction 
 Positive direction sensor hole 
 Response time 
 0.5 seconds 
 Ambient temperature 
 0 ~ 40 ℃ 
 Ambient humidity 
 20 ~ 90% RH 
 Size 
 H51 × W102 × D43 mm 
 Weight 
 170g