Twin Pillow Block Linear Ball Bearing IPPSWN24G 1.50" Open - Precision Plus Self-AligningOpen twin linear ball bearing pillow block with a 1. 5" ID (inner diameter) bearing inside an aluminum alloy housing. Part of the Precision Plus self aligning series, the IPPS twin bearings feature two grease zerk fittings, known as lubrication ports, located in the pillow block. Twin Double size equal to two standard bearings mounted back to back Open shell design for use with rail supported round linear shafts Temperature Range: 4 +176F ( 20 +80C)