RULE THRU-HULL LIVEBAIT PUMPS These 12 volt cartridge style 12v electric pumps are designed for thru-hull mounting to pump water through a livebait tank. Rule livebait pumps are compact vibrationless and run silently to eliminate noise annoyance - keeping fish calm healthy and fresh. These pumps incorporate a Rule 360 500 or 700 GPH cartridge pump with a 3/4" threaded nylon thru-transom pick up fitting lock nut washer and strainer.The pump motor can be easily removed from the thru-hull fitting for cleaning or replacement of the motor cartridge unit even when underway. 2 types are available - Straight fitting or angled fitting. All pumps have a 20mm hose outlet and a threaded inlet complete with fine filter nut and washer.