Twin Plain Linear Bearing Pillow Block - PW06C 3/8" Closed, CompensatedTwin plain linear bearing pillow block with a closed 3 8" compensated ID bearing inside a mountable aluminum alloy housing. The bearing has an anodized aluminum shell and is lined with self lubricating FrelonGOLD, ensuring maintenance free operation, low friction, and durability in extreme conditions like high temperatures, dirt, and vibration. The twin design resembles two blocks positioned end to end Twin design is like placing two blocks end to end