Twin Pillow Block Linear Ball Bearing IPPSW12G 3/4" Closed - Self Aligning Precision PlusTwin Linear Ball Bearing Pillow Block with a 3 4" ID (inner diameter) crowned shell self aligning bearing inside a housing made of aluminum alloy. The IPPS products all come with a grease zerk fitting, a small hole in the pillow block which is also called a lubrication port. Twin bearings come with 2 lubrication ports. Temperature Range: 4 +176F ( 20 +80C) Variant ID Sizes: Available from 1 4" to 2 Inch Series, 8mm to 50mm Metric Interchangeable: Size