Pro Fitness Treadmill Model jx-260 front & back Rollars.
These are used and taken off my old treadmill.
Might be compatible with other models.
roughly 50cm long, but you can find exact measurements by googling the make of the treadmill.
the rollars show sign of use - please see picture.
collection at the moment - based in coventry.
the screws are not included, but listed in a separate auction.