GP 11A: Alkaline battery, cylindrical, 6 V, 38 mAh at reichelt elektronik
One (1) x Vinnic 11a L1016 Alkaline Battery 6v Blister Packed - Used in Doorbells, Car Key Remotes, Lighters, and many other applications: Amazon.co.uk: Electronics & Photo
Mjkaa 5pcs L1016 11a6v Alkaline Battery 11a 6v Dry Batteries For Remote Control Car Boat Watch Toy Calculator - Primary & Dry Batteries - AliExpress