The MP5SD (German: Schalldämpfer; English: Sound suppressor) is a variant of the MP5 equipped with an integral suppressor. The MP5SD is a submachine gun manufactured by Heckler and Koch that chambers the 9x19mm Parabellum round.
Although the MP5SD itself does not appear in the Rainbow Six universe, there are two variants of the MP5SD that do. These variants are the MP5SD5 and the MP5SD6.
Terrorists throughout the world fear Heckler & Koch's MP5SD. Its integral silencer is so effective that the report of the bullet is minuscule compared to the click of the bolt operating. RAINBOW uses the 9mm MP5SD5 whenever both accuracy and stealth are essential.
The MP5SD is, function wise, very similar to its unsuppressed counterpart. Overall, the weapon can act as another MP5 with very little difference in function, minus its inability to attach any other barrel attachment.