Blum TANDEM plus BLUMOTION Soft Close, Full Extension Drawer Slides w/Locking Devices (T51.1901) and Rear Brackets  Models: 563H5330B (21'') 563H4570B (18") 563H3810B (15'') Description - Full extension concealed drawer runners - Face frame or frameless cabinets - BLUMOTION soft closing - TANDEM smooth-running action - 1/2" (13mm) to 5/8" (16mm) drawer thickness - Four-dimensional adjustment clocking devices - 100 lb. static load capacity  - Made in the U.S.A Includes 6 pairs of slides (6 left & 6 right slide) 6 pairs of 4-way adjustive locking devices (6 - T51.1901L & 6 - T51.1901R) 12 rear mounting brackets 295.3750 (FOR FACE FRAME CABINETS) Mounting Screws #6 5/8"