Johnson CM30P7-1 Compact Water Circulating Pump 24V 

CM Series Circulation Pumps are a line of compact centrifugal pumps which combine high flow rates with very low electric current consumption, making them ideally suited for circulating fresh water in live fish tanks, heating and cooling systems. But not saltwater.

Technical Specifications
Pump Body: PPA
Impeller: PPA
Shaft: Stainless Steel
Liquid: Water/glycol mixture; max 60% glycol, fresh water
Liquid temp.: Min -40°C, Max +100°C
System Pressure: 2.5 Bar max
Port Size: Ø 16mm (5/8") hose
Dry Running: Max 30 mins
Input Power: Max 27W
Mounting: Separate universal bracket for flat services
Motor: 12/24V DC enclosed (as per IP67) permanent magnet, ball bearing mounted motor, designed for continuous operation
Dimensions (LxWxH): 177 x 68 x 85mm (6.97" x 2.68" x 3.35")
Weight: 0.6kg (1.3lbs) with bracket