ITEM NAME:2 Pcs 12 mm SC12UU Linear Ball Bearing Slider Slide Bushing Replacement CNC A#S Product Description Description: 100% Brand New and High Quality Model: SC12UU Shaft ID:12mm Shaft OD:21mm Quantity: 2pcs Weight:191g Included: 2 x SC12UU Ball Bearing Slide Bushing.Model: SC12UU. Included: 2 x SC12UU Ball Bearing Slide Bushing. Shaft ID:12mm. Shaft OD:21mm. If item is defective after 3 months, you can still send it back to us. We will send you a new one after receiving the defective item.