A circuit that draws 10 ma powered by a 9 volt rectangular battery will operate about 50 hours: 500 mAh /10 mA 50 hours The cell voltage of alkaline cells .
9V. Classification: Alkaline. Chemical System: Zinc-Manganese Dioxide (Zn/
PANASONIC power battery, 9–volt block. Compatible with: 9–V block/4022/6LR61
Energizer Max Alkaline 9–Volt Battery – 595 mAh – 9V – Alkaline – 9 V DC – 2 / Pack. Long-lasting power source; Designed to protect your expensive electronics