Martindale TEK100 Non Contact Voltage Detector
  
This is suitable for detecting 100V to 600V AC without requiring physical contact with the conductor. The presence of any voltage between 100V and 600V AC will generate an audible tone, together with a red visual indication.
The integral self test activates the sensor in the tip of the tester at 50Hz as well as checking the battery and LED. The entire circuit, not just the indicator LED, is therefore tested.
This proves that the unit is fully functional and avoids the need for a separate proving unit.
The only non-contact detectors with a built-in proving device that really proves the entire circuit.
Voltage Range
100 to 600V AC
Frequency Range
50Hz to 50kHz 
Sensitivity
3mm for 100V, 50Hz
23mm for 240V, 50Hz
Distances are from the tip of the unit to a flat PVC twin core and earth cable suspended in free space.
Indication
Visual: Red LED
Audible: 2kHz Tone
 
General Specifications
Integrated self test proving unit
Operating Temperature: 0C to 50C
Overvoltage: CAT III 1000V, CAT IV 600V
Supply: 9V battery alkaline battery, MN1604 / PP3 or equivalent
Housing: Flame retardant ABS
Dimensions: 202 x 32 x 22mm
Weight: 140g approx (excl. battery)