4x Double Zinc Alloy Shower Door Roller (2 top double +2 bottom double )
The 23mm diameter wheel shower roller is suitable for curved doors, for glass doors of 4-8mm thickness, and the upper and lower wheels are bigger than12MM(0.47in) glass apertures
These rollers fit glass where the distance between the centre of the fixing hole and the edge of the glass is 18mm.
top wheel:adjust the screw to adjust the up and down position of the shower door roller.
bottom wheel:The height of the lower wheel spring is automatically adjusted according to the height of the upper wheel.