Replacement Door Rollers for Sash Windows These are replacement door rollers for sash windows. We recommend replacing them if the sash window becomes difficult to open and close. These door rollers have been developed for general use in replacing door rollers in many sash windows. They are designed for both left and right sides, so two door rollers are needed per sash window panel (four for a sliding window). These are newly designed general-purpose adjustable door rollers for replacement in renovations. Despite their extremely compact size, with a frame height of only 18.5mm and a thickness of 9mm, they offer sufficient smoothness and durability. Installation is done by attaching to the side of the lower frame of the sash window, and the height of the roller can be easily adjusted with a screwdriver from the end of the sash window. Material: Frame: SUS430 Wheel: Polyacetal, oil-impregnated Adjustment screw: SUS430 Spacer: SUS430 Specifications: Maximum panel weight: 30Kgf / 2 pieces Durability: Equivalent to 50,000 open/close cycles Height adjustment range: 20+3.5mm ※Price is for one door roller.