The vents, (slots) go to the rear:
http://www.canuckaudiomart.com/view_images.php?cat=Amplifiers&catnick=amplifiers&cfid=100713&image_id=701909
http://www.canuckaudiomart.com/view_images.php?cat=Amplifiers&catnick=amplifiers&cfid=100713&image_id=701909