Each library handles its laptops a little differently. Some libraries create MARC records in WorldCat to match their laptop type and just add an item record to it for each laptop they need to check out. To search for those records, you might want to use something like "ti:dell AND x0: Object". Switch out the "Dell" part with your make/model of computer. Once you find your make/model in WorldCat, take note of the OCLC number, search for it in WMS Circulation and add your items to it.
There are other libraries that just add a temporary item record for each item and circulate them that way.