Blums newest generation of TANDEM plus BLUMOTION concealed drawer runners offers four-dimensional adjustment, elongated holes for depth adjustment, bottom mount holes and exceptional load capacity (100 lb. static load). With TANDEM plus BLUMOTION concealed runners, customers only see the beauty of the wood drawers while experiencing the quality of motion and soft closing they have come to expect from Blum products. TANDEM plus BLUMOTION concealed runners are made in the USA at Blums North Carolina facility. This is just one example of Blums commitment to manufacturing in the US, for the US. TANDEM plus BLUMOTION is mounted discreetly beneath the drawer and has the quietest opening and closing action available. This top-of-the-line concealed runner is the industry choice for dovetail drawers in high-end cabinetry, in either face frame or panel. For installation on both face frame or frameless cabinet drawers Fully concealed drawer slides are full extension Designed for drawers that have 1/2" to 5/8" thick sides. Drawer box must be 15" deep (front to back dimension of the exterior of the drawer box). Packaged in pairs with side adjustable locking device, rear mounting brackets, screws and instructions. Package quantities vary based on chosen product.