Having been let down by my original battery supplier (they never arrived from the Philippines) I ordered new ones from Cool Components on the weekend, this time 2x110mAh 3.7v LiPo cells. Impressively, they arrived today and they are much smaller than I thought!

Definitely going to fit two of these on my wrist 🙂

Now I just need to order some JST connectors to wire them up in series and get some leather to make a strap!