Well, a search of “SDMX18R” brings some hits, some of which are:
http://www.beachaudio.com/Sandisk/Sdmx18r-002gk-A57-p-293996.html
http://www.buy.com/prod/clip-plus-4gb-mp3-player-black/q/loc/111/211933819.html
http://www.sureneeds.com/manufacturer-sandisk.html
And one from the Google cache:
Apparently they come in at least black, red and blue, and 2GB, 4GB and 8GB capacities.