I have found that the bigger Walmarts carry some computer hardware (i.e. optical drives, modems, sound cards, video cards, etc) and some of the smaller Walmarts do not. I am guessing that many of the larger Walmarts will carry the Liteon 166S/165H DVD-ROM drive. With a May 2003 manufacture date, the stock I saw was probably 166S, but I don't know for sure because the box does not state which model is packaged inside. Last weekend, I visited a smaller Walmart and it had no optical drives at all--so it is best to look in the larger Walmarts. These "larger Walmarts" don't have to be Walmart supercenters. We don't have supercenters here where I live--the store I saw the Liteon DVD-ROM drive was not a supercenter. But Walmart supercenters are big and should certainly carry computer hardware--so if you have a Walmart supercenter and want this Liteon DVD-ROM drive, look there. A great place to look (if you don't have a Walmart supercenter) is at newer style regular Walmarts (I'm not referring to a supercenter)--since they seem to make the newer Walmarts bigger and better than the older ones. You can look in the smaller Walmart stores for the Liteon DVD-ROM drive, but I think you'll have better luck looking in a larger Walmart store. The store I saw the Liteon DVD-ROM had the large part of an entire aisle dedicated to computer hardware.