Plain Linear Pillow Block Bearing PM25C 25mm Closed, Compensated IDClosed Plain Linear Bearing Pillow Block with a 25mm ISO Metric inner diameter and a compensated running clearance of 0. 0015" per side. A mountable standard sized aluminum housing encloses the bearing, which features the renowned self lubricating liner made from FrelonGOLD for maintenance free performance under harsh conditions such as extreme temperatures, dirt and vibration. Optional liners: corrosive chemical resistant FrelonJ & FDA compliant