The TR 25 is a great optic and on a low profile mount on the MP5 co-witnessess perfect. I have a SPARC on a AKS47U and it also is superb plus it is NV capable and comes with a optical doubler. The battery is a little uncommon in that it is like 1/4" thick, not a standard off the rack radio shack/walmart selection. However, for my UMPs I have an Eotech on the .45 and a Kobra on the 9mm. The gun tops out at 100M so magnified optics are kind of a waste and the Kobra/Eotech have large optical surfaces and sight acqusition is immediate.
