T-NUT bearning holder for 2020 aluminium profile

Use screw M4x20

You can use any bearing external diameter not exceeding 30 mm and an inner diameter of not less than 4 mm

Insert into the slot aluminum profile and turn 90 degrees clockwise.Insert the second half and also turn 90 degrees.Insert the screw, washer, bearing, washer and slide up to the stop.Tighten the screw.