Here is a pic of a 5-5-2 (top)& 6-6-3 long reel glass. Typically the 5-5-2 has the chrome around the windows, etc. & will indicate "Credits Played". The 6-6-3 LCDs are smaller thus the size & spacing of the Winner Paid, Credits & now "Total Bet" windows is slightly different. Ironically a 6-6-3 display fits a 5-5-2 glass better than a 5-5-2 in a 6-6-3 glass. Most people don't even notice but if you're anal about your machines like me, you will notice. Second pic shows a 5-5-2 behind a 6-6-3 glass. It doesn't exactly line up but close.