HESTRAPower Heater Gauntlet Electric Ski Mitten

how many uses do you get before the battery need to be replaced

Do these gloves come with a charger and enough batteries to power both gloves?

The picture shows the Hestra mitten, but the description shows a Hestra glove - so which is it? I am interested only in the mitten.

What size/voltage/model# is the battery? can you swap batteries in the field and carry spares?