eBay
Here we have a current issue UBACS Under Body Armour Shirt, as worn underneath Osprey body armour etc.
 
Tan coloured central area is made from wicking and heat dispersing Coolmax fabric.
 
Sleeves and shoulder area made from hard wearing poly cotton in genuine UK issue Multi Terrain Pattern camouflage, uniquely designed for British forces deployed in the greener areas of Afghanistan.

This version has a green central core instead of the earlier tan colour, and no padding in the sleeves making them easier to roll up in hot climates if desired.
  
Large pockets on the upper arms, along with velcro panels to which unit insignia, medical patches etc could be attached.

Button adjustable cuffs.
 
New unissued condition..
 
Size SMALL.  - 160/80 - Fits up to 36" chest maximum.
 
Please note these are smaller than the equivalent 'small' size in the earlier versions with padded arms etc...