Penguin electronic metering pumps are positive displacement, non-hydraulic, solenoid driven, diaphragm type pumps. In the Series PB/PE/PEP pumps, the electronic circuitry is EMI resistant, incorporates automatic reset thermal overload protection, and employs a MOV for lightning protection. Pump drives are encased in water and chemical resistant housings. Most models are UL listed for outdoor and indoor applications and are CSA and NSF approved.