This is a Li-Poly 2800Mah 11.1 volt transmitter battery and charger kit. It fits the Futaba 3PK and the Airtronics M11,MX3 transmitters. These super high capacity, light weight packs are only 180 grams compared to 235 grams of an 8 cell AA pack. This reduces the weight of your transmitter considerably and lasts a good 18 to 20 hours of run time! The biggest feature of this kit is the low voltage cutoff built into the pack. So even if you leave your radio on overnight it will protect the pack from over discharging.Included in this kit is a very user friendly LiPoly 3 cell peak charger. This simple to use charger just plugs into the wall and shows red light while charging and green light when it done. It takes about 2 ½ hours to fully charge a discharged pack. Assembled in house to assure the best quality.