PSDY Chair and Bar Stool Swivel Plate, Race Nylon Ring Bearings for Long Lasting Durability 7" diameter - square - made with steel plates and full race nylon bearings High quality - torture tested 500,000 times under a load of 500 lbs. 3/4" tall, 7" square, slotted mounting holes on 5.5" centers - will accommodate 5"-6" mounting patterns Smooth gliding swivel - may feel stiff by hand, but it becomes much easier when installed due to weight being on it Made in the use - full 360 degree rotation - mounting hardware not included