New system developed for versatility – There is a peristaltic pump that pumps 30 ML ( 1 OZ) / min (one shot). For example to empty a gallon in  approx. 30 days – program for 4 mins per day. System can be programed as required to allow as many shots as required per 24 hour period. It will fit a 1 US Gallon container or 5 liter container. The system operated on D Cell Batteries (not included) or rechargeable battery (included with US charger- Can be used in Europe with a US adaptor.) If used to empty a gallon or 5 liter unit per month – rechargeable battery life can be up to 90 days before a charge. You can alternate use from one battery type to the other – at the flick of a switch. The is a slot in the front door to check fluid levels without having to open the unit.