This carpet knife has an exceptionally high quality 3" long blade.  It keeps its extra sharp edge longer than others.  Can be used on all types of carpeting.  It also features a specially shaped positive grip handle.  This knife is GREAT for opening carpet seams.  By inserting the knife underneath the seam at a 45 degree angle and pushing the knife forward, the slight curve of the sharp blade allows the professional to feel as they cut open a seam and confirm that they are, in fact, cutting the seaming tape at the seam and NOT the tape and carpet at the seam.