The compact comes with the 10 round compact magazine, and the 13 round full size magazine with grip extender, it makes it the exact size as the full framed XD. Perfect for carry and range duty
It’s a magazine 
and the 5" barrel version comes in fullsize and compact as well. 4" and 5" both avail in fullsize and compact grip’s.
Excellent choice tho, i am going to pickup a XD40SC to compliment my 45C soon
And i love the color, i was going to get it, but ended up with Black on black… I think my next will be the stainless steel slide