Well after rebuilding my AP Helmet for the third time (and i'm sure i'll do it again!) .... i have now painted it Matt Black inside (after comments from Mr's Cherrington and Hailes! Lol) .... and have managed to fully load it with a ROM FX, 2 x 4AA Battery Packs, 2 x 9v Battery Packs, a Fan, built in Mic, and Hovi Speakers and some nice comfy padding!
.... and it still fits on me noggin!!! Wahooh! 8)