sourcing map 6mm Linear Ball Bearings LM6UU Extra Long LM6LUU, 6mm Bore, 12mm OD, 35mm Length 2pcs

Exactly as described linear bearing

You'd get smoother action from putting sand in a metal tube. Poor quality bearings, rough movement and quality.

I bought one of the sets of replacement bearings for the Anet A8 printer, only to discover that the Z axis requires two of these long bearings. Not many suppliers make that clear, and seem content to sell the short bearings (fine for the X and Y axes, but only half the length required for the Z axis. These Extra Long bearings are just the right length and are a reasonable price for what, at this stage, seems like a reasonable quality product.