g&p Force Recon m4 - battery help

[lloydyd123]

Hello guys just wanted some advice on the new gun i have just purchased. G&p m4 force recon.

Link here to gun (http://www.landwarriorairsoft.com/ai...l-system-p3668)

Basically i know it runs on a 7.4v lipo, im just unsure as to what exact battery i should use for it? Anyone know the best make/rating of 7.4v lipo i should use?
Also what are peoples opinions on peq boxes to store the battery? Is it better to get a battery sleeve and side mount it?

Any suggestions/help much appreciated. Thankyou