JET Rail Linear Ball Bearing Higher loads 3/4" Jet Rail Pillow Block Dynamic Load = 1200 Lbs. Moderate  loads 3/4" Ball Bearing Pillow Block Dynamic Load = 470 lbs.   25 Feet Per Second   10 Feet Per Second Sealed for life rollers Balls open to contaminants when seal is torn or by-passed. Repair kit enables you to replace rollers and rebuild bearing block in the field Throw away Rolls over debris and has a scraper option to clear roller pathway Entraps debris and fails, scoring shaft. Balls can fall out.   Low noise, smooth linear motion. Minimal resonant energy passed back to system Great for camera stands and moving stage platforms where speed, load capability and quiet operation is paramount. Noisy - "zings" down the shaft Transmits vibration into shafting. Poor choice for optics and vibration sensitive equipment Fixed and Adjustable floating blocks for shaft misalignment No adjustments for side-to-side misalignment