| Model 156A Charged-Plate Monitor | Trek |
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 | - Monitor Voltage range 0 to ±1100VDC or peak AC
- monitor and maintain your ionization program
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| Model 157 Charged-Plate Monitor | Trek |
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 | - Monitored Voltage range 0 to ±1020VDC or peak AC
- ideal for monitoring static charge in a manufacturing facility
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| Model 158 Charged-Plate Monitor | Trek |
|
 | - Dependable and portable ionization Monitoring
- Monitored Voltage range 0 to ±1110VDC or peak AC
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| Electrostatic Voltmeter - Model 159H H | Trek |
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