3/4" drawer side requires full extension. Interior depth of at least 18-3/4" needed for 18" drawer. For inset applications, add drawer front thickness to minimum interior depth. Mounting options include undermount to drawer, side-mount to cabinet, and rear-mount with bracket. Look for Blum Rear Mount for more information. Locking devices are necessary. Check out Blum Locking Device for Tandem Drawer Slides. Also consider searching for Blum Tandem Accessory Kit for more help.