Review on Premium 15 300mm Guideway Carriage Bearings by Happybuy: Optimal Performance and Durability by Dragan Nelson

Carriages are high quality - strong, all deflections are within norm. All the blocks I received were black and silver, not tri-color as you see in the listing. The seller assured me that they are identical in everything except for the color. The packaging comes in a cotton envelope from China with bearings installed on the guides and in plastic bags. There's a lot of grease on everything, so be prepared to wash things first. You should then use the bearing grease of your choice. Also included are some plastic caps to cover the screw holes in the installed rail and plastic caps to hold the ball bearings in the blocks if you need to remove them from the rails. The only thing to note is that this rail profile is slightly different. than a standard 15mm frame - the shoulder is shorter on them so these bottom brackets will not fit. As a result, I was unfortunately not able to use the bearings as intended, but I will probably find an alternative use for them at some point.