Like Tex said, Glock 17.
(Just providing links so you're more confident in the answer)
http://en.wikipedia.org/wiki/Glock_17
Scroll down, you'll see Glock 18 is selective fire varient of the 17.
http://www.remtek.com/arms/glock/model/9/18/
Has the dimesions of the Glock 18 (Sorry, even I can't find a government sales page for RealSteel Glock 18)
http://www.glock.com/english/glock17_tech.htm
Dimensions of the Glock 17