I learned all of these letters/numbers from the Cruiser RV website to help me distinguish between the TT models made by Cruiser. Just go to cruiserrv.com and click on the floor plans for the Fun Finder, Shadow Cruiser etc. and you will see the letters/numbers match up with the model/length/features etc. owners on this site are referencing in their posts. Sincerely, Jeepin-family a/k/a X214WSD (24', dinette slide, center entertainment console, walk around queen bed, large rear bath). We came close to being an X215WSK (24', sofa slide, center entertainment console, rear bath, outdoor kitchen and an X210UDS (21', dinette slide, walk around queen bed, smaller rear bath) before deciding on the X214WSD. Good luck!
P.S. To further confuse you, I believe Cruiser is now using 'F' instead of 'X' on all of the TT models.
2013 FF 214WSD
2011 Jeep Grand Cherokee-5.7L V8 HEMI
Equal-i-zer 10K wt./sway hitch