This page tracks Launch 3, planning in progress.

36” Qualatex silver “foil” balloon

Approximate weight of 37g, approximate internal volume of 0.1cu m before envelope stretching.

This means they can lift payloads of approx. 60g (or slightly more if you allow for stretching). However experimenters typically aim for payloads of the order of 20 - 40g per balloon in order to attempt to make them float.

http://www.randomengineering.co.uk/Random_Aerospace/Balloons.html

HABTRK

Single Energiser Lithium AA or AAA

AA - 3,000 mah, 15g AAA - 1,250 mah, 8g