Jack stands keep a vehicle propped up and stable after lifting it with a jack. It is important to never work under a vehicle supported only by a jack. If anything interferes with the floor jack, or if the vehicle is unbalanced on the jack or on an uneven surface, it may cause a serious safety issue. Floor jacks also use hydraulic pressure to hold up the vehicle, and if a seal fails, the jack may lose pressure quickly. Jack stands will minimize the risk of a lifted vehicle dropping unexpectedly, and should be rated to support more weight than the weight of your heaviest vehicle. At O'Reilly Auto Parts, we carry light- to heavy-duty jack stands to support most cars, trucks, SUVs, and more.