Battery junction has two different styles of tenergy 18650 batteries, both are 3.7v, rated 2600 mah. One is a flat top and the other says "pack-building tabs". Which one of these should i get for a BSB i'm ordering this week? I'm getting the tenergy RCR123A 900mah batts from the link above for 6 volts, but want one for 3.7v too...