CNBTR 4Pieces 6x30x13mm Plastic Coated Sealed Bearings Steel 606ZZ Deep U Groove Guide Pulley Rail Ball Rolling Bearing Wheel Orange

I am using them in a system to lift insulation panels in a greenhouse. They seem well designed. You can fasten the shaft to the bearing center without interfering with turning.

Used this product to make a tubing straightener for fuel lines for a car. Works well

Made a brake line straightener works well.

I purchased these to use on a track system I made for a router sled. The track is made of uni-strut so the wheels had to be a very specific size. They worked like a champ and I'm able to mill down large slabs of wood.

Price is good, item come with v-groove, I wish is solid flat , but useable , good to me

These fit perfectly on one side of Unistrut. Used unistrut for the guide rails for my router sled.

Good buy

will work for my application