q's about phat differences and "reg"

[etertay]

hi i just ordered my Nintendo Ds from eBay (risky i know)

and i just realized that im not entirely sure which model it is

the ebay selling account says

"nintendo ds reg" what does "reg" stand for

also is this model a phat or lite

i need to know because i want to order an r4 before i go on vacation

here is pic of ds

http://1.bp.blogspot.com/_tn44wIP0bAw/TEOLRxx833I/AAAAAAAAACs/FXCz_XVNhz0/s1600/ds.JPG

thanks sooo much