The DF4900's olympic bar glides on four precision linear roller bearings that ride on polished solid steel bars. The DF4900 moves effortlessly to recreate free weight feel but with the safety and stability of a smith machine. We encourage you to find another linear bearing machine in this price range. You won't. Rear plate holders are added to the back for convenience loading and unloading the machine. As far as smith machines go, this one may be one of the most versatile on the market. Deltech Fitness designed this machine with a pull up bar and provisions for future upgrades such as the DF830 Plate Loaded Lat Attachment, or the DF838 Stack Loaded Lat Attachment.  Add a pec attachment like the DF832 on top of either lat attachment to tackle another muscle group and further expand your workout without taking up more space. Forget a gym membership! Pick up a Detech Fitness linear bearing smith machine today!