These devices are seriously impressive hydraulic lifting devices which can be rolled into place below a vehicle with complete accuracy, thanks to the attached multi-directional wheels and castors.
They also have an essential safety overload valve to prevent an operator from trying to get a jack to raise a vehicle which exceeds the device's assigned weight limit.
There are three main considerations when deciding which floor jack to buy - fristly that a device has an adequate load capacity for raising your vehicle, secondly that the lifting height range of a jack is suitable and finally whether it is standard or low profile jack.
If you own a sports car, for example, the chances are the chassis will be quite near the ground, so you'll probably need to buy a low profile jack which is capable of getting underneath it.
Most jacks come with a decent warranty so you'll be protected in the event that a problem arises. Thankfully, however, jacks are generally very reliable indeed and should operate efficiently and safely for many years.
Just remember to give a jack a good clean from time to time to remove a build up of dust, dirt, oil and grease on the body. You'll also need to purge the hydraulic system of air occasionally and replenish the oil in the device.