In a nutshell, when you buy the Umarex T.A.C. Converter XBG CO2 BB Pistol Combo, you get the XBG CO2 4.5mm BB Pistol preinstalled in the T.A.C Converter, you also get the included fore-grip which is renovable by the way can coudl be used stand alone on any other gun with an under barrel Picatinny rail.
Keep in mind that this combo kit only works with the XBG Pistol since there are no included adaptors for the other Umarex pistols designed to work with the T.A.C Converter. (H&K USP, S&W M&P40, XBG, CZ Enforcer, Walther P99 DAO, SA177).
The addition of the T.A.C. Converter to the XBG really improves the shoot-ability since the rear folding stock allows for a much more stable hold position. You also have the addition of whit dot sights front and back with the rear sight being adjustable for windage only. I would recommend a compact light weight red dot sight for this gun since using the included open sights are hard to keep in focus because of how close the rear sight ends up being to your eyes when in the shouldered position.
With the top, bottom, and side picatinny rails you can add litterally all types of accessories to this package including a tac light, laser, optical sight, red dot, folding metal sights to name a few.
The XBG BB Pistol has a nice combincation of 400+ fps with tuns of shots per CO2 and respectible accuary with easy access to the Drop out metal BB magazine.
For under $60 in our Canada Replica Airguns store this is a really fun package!