This metal frame supports your twin size or full size mattress and boxspring and provides a low profile support. This frame will hold your box spring 4.125" From the ground using the casters included with it. It comes with four caster feet, is 67.875" In length and uses nut & bolt assembly. For an extra low profile frame, you can purchase four additional "short glides" to replace the rug casters. This would then lower the frame to 2.5".