These Glass Holder Pulley made of stainless steel material(Include the 2 wheels), for 5mm thick glass use.Easy to install !Just install these products to clamp corners of the glass(bottom).Then Set them into the sliding guide.In order to make this type of two-wheel glass mobile door wheel installation more solid and not easy to fall off, you can put a small amount of glass glue at the bottom and inside of the groove, the effect will be better.
