The Fish Mate P21 is for ponds and large aquariums, the P21 will dispense food slowly over a 5 hour period for approx 21 days. The fully weatherproofed P21 may be pole-mounted at water's edge or suspended over the water. Adjustable feed quantity and timing for all fish foods. Reliable and accurate quartz timer

Over 1 year's continuous use from 1 AA battery with a battery condition indicator. The Fish Mate P21 feeds approximately 21 daily meals, served over several hours while you are away. This keeps fish active and reduces danger of overfeeding.