Double Plain Linear Bearing DFPM30 30mm ID Square Flange End, Precision ClearanceExtended Plain Linear Bearing with a 30mm ID consisting of a square flanged aluminum housing (end mount) with a precision ID running clearance and a self lubricating FrelonGold lining for maintenance free linear, rotational or oscillating motion in harsh conditions like extreme heat, dirt, and vibration. Extended Size Housing With Bearing Included Square Flanged End Mount Closed Shell Precision ID running clearance (0. 0005" per side) Self Lubricating