This makes lining up cabinets a breeze.  I loaned them out several times already and everyone says the same thing - it makes hanging cabinets, especially uppers, much easier.  I remodeled my kitchen and these allowed me to both pull the cabinets together tightly as well as flush at the face.  After getting them flush/tight, you drill a pilot then pop in a screw and you are good to go (mount to wall of course).