Panasonic Rechargeable Battery
VL2020
VOLTAGE: 3V
DIAMETER: 20.0mm THICKNESS: 2.0mm
Chemical Compound: Vanadium Pentoxide Lithium
Brand new Genuine Panasonic Rechargeable Battery VL2020
This is a replacement battery for the following Key fobs
E38 E39 E46 E53 E60 E61 E81 E83 E87 E90 Z3 X3 M3
fits Diamond Keys as well as many BMW key fobs from the early 2000's
The keys Recharge (using induction) when in the ignition but as with any rechargeable battery they are only good for about 1000 charges.
The keys are sealed and will Normally cost between £140 - £175 to purchase from BMW,
But with this battery you can simply replace the battery yourself, there are many guides on how to do this on the internet.