4 Pcs SBR20UU 20mm Aluminum Open Linear Slide Block for SBR20 20mm Linear Guide Rail

I bought these to replace a damaged bearing (my own fault for not installing limit switches on my home built router) from a kit I ordered on AliExpress. Works as good as expected, shipping was fast, and the price was fair. Hopefully I won't need these again as I have 3 spares now, but if I do I'll get these.

Perfect bearing assembly for my cnc machine. Smooth operation of bearings. Met my expectations. Thank you