Basic 2-inch nylon rollers with a 4-inch stem, bag of 10. These springs are non-bearing rollers, meaning there is no ball bearing inside, the stem just rides on the nylon wheel. they are the cheapest option and work fine on lightweight residential doors that do not get opened more than a few times a day. This 7/16-inch diameter stem fits standard residential hinges. For 2-inch track only. If you just need rollers that are quiet and do not care about longevity, these do the job. But if the door is heavy or gets heavy use, step up to the 11 or 13 ball bearing version.