I got the Basic set and this "Complete Bed Protector Set" that comes with protectors for the mattress, box spring and 2 pillows (for a queen).  All protectors fit perfectly, but if your mattress is more than 11" thick, I would look at the Basic set because it has way more space to fit mattress toppers, etc.  If you want a snug fit on the mattress I would go with the Complete set (fits a 10"-11" mattress perfectly).