what battery this ring have? Those rings are waterproof?

I own a samsung door lock and have two NFC rings that I would like to change for two new ones.
I bought a read/write device that would not do the job wrong frequency is 13.56mhz the correct frequency I know I can change the lock code bur that is difficult as family have fobs
The contactless ring is my best buy. I wear latex gloves when shopping and ring works never had any problems saves cleaning cards

Our ring contain no battery and they are all water resistant (tested up to 50m depth!).

@david-verbeck Nice idea David! Unfortunately it's unlikely this would work effectively using NFC, as you'd need to be really close to the reader to register (< 4cm). You'd then also need to have a powered reader around your neck also.