This sliding glass door roller assembly is constructed of corrosion-resistant aluminum housing and features a height-adjustable housing. The concaved (grooved) edge wheels installed in these roller assemblies are constructed of plastic and include steel ball bearings for smooth and long-lasting operation. The wheels are designed to glide on a single raised aluminum or steel track. This item includes only one roller assembly per package, but a total of 2 roller assemblies are required for each sliding door. These roller assemblies are used to repair patio sliding doors with missing, damaged, or malfunctioning roller assemblies. Installation is easy to install with a few simple tools. Refer to dimensional line drawing to match product specifications. This style roller is used on International and similar styled patio doors.