The Mk1 IBP-1 4400 mAh battery is a long-lasting lithium ion rechargeable battery pack compatible with the RICO Mk1. The IBP-1 uses a cam locking mechanism to ensure quick and secure swapping of batteries in the field.
Run time depends on the scope, its settings and the temperature, since cold drains lithium-ion faster and features like video recording add load. The IBP-1 is a 4400 mAh pack for the RICO Mk1, and its cam lock makes carrying and swapping a spare quick.
The ones the scope was designed around. For the RICO Mk1 that's the IBP-1, a 4400 mAh rechargeable pack that locks in with a cam mechanism. Using the correct pack avoids the fit problems you can run into with generic cells.