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 waters edge or suspended over the water. Reliable and accurate quartz timer. Over 1 year's continuous use from 1x AA battery. Battery condition indicator. Feeds approximately 21 daily meals while you are away. Food served over several hours - keeps turtles active and reduces danger of overfeeding. Adjustable feed quantity and timing for all turtle foods. Easily suited to all ponds and large aquariums.