Nickel Metal Hydride (NiMH) batteries are your best when it comes to a durable battery that's going to last. Less sensitive than a Lipo battery and not susceptible to battery life memory loss like Nickel Cadmium battery packs; NiMH batteries offer the best of both worlds. Great for entry to mid-level players who just want to enjoy the game without having to worry about their batteries. The stick configuration is designed primarily for use in AK47 and AK74 AEG platforms where the battery must be stored within the small confines of the upper receiver.