BATTERY-MH1

​Voltage (9V): This is a standard 9V (PP3) size, commonly used in smoke detectors, guitar pedals, and handheld microphones.
​Chemistry (Ni-MH): Nickel-Metal Hydride is a common rechargeable chemistry. Unlike older Ni-Cd batteries, these don't suffer as badly from "memory effect," but they do perform best when managed correctly.
​Capacity (250mAh): This tells you how much energy the battery holds. A 250mAh rating means it can theoretically provide 250 milliamps for one hour (or 25mA for 10 hours