Let him buy his own Leatherman at the PX in theatre as they will be cheaper.

Instead, buy him a black diesel powered mambo for those lonely times between patrols / stags.
Don't get him a Leatherman - he can pick one up in the PX when he is out there (assuming he will at least occasionally get to somewhere quite big, with Americans). They used to be half UK price - probably not so good with the Exchange Rate now, but almost certainly still a lot cheaper than UK (and they do them in anodised black finish).