Recommended Eken H9 Compatible Accessories + Batteries?

Hi all,

I bought it from this deal: https://www.ozbargain.com.au/node/265557.

Questions:
1) Can anyone who's purchased from lightinthebox.com confirm whether the battery has rounded corners or is perfectly squared? Apparently there are 2 version floating around - Post Jan 16 models have rounded batteries.

Please recommend a compatible battery if possible.

2) Can someone please recommend a compatible selfie stick/monopod + a head mount/strap?

Planning on using this for tough mudder which is in about a month.

Cheers.