When you use your Stabila 96, 196, or tech fixed length level to see which jamb side to trim to adjust for unlevel floor, you can instantly find out not only which side to cut, but precisely how much to cut, by adding a How Far Out level gauge to your Stabila. Same with scribing door edges to fit out-of-plumb pre-existing jambs. Go to www.howfarout.com to order yours now.