Experience superior cutting performance with this replacement blade & housing that is designed to perfectly fit Dahle 550, 552, and 554 Rolling Trimmers (Generation 2). The blade is self-sharpening so you wonβt have to worry about it going dull. Graduated edged blade has the capacity to cut and self-sharpen in either direction thus guaranteeing renewed sharpness with every use. Extremely sharp, this replacement blade can cut slivers on the paperβs edge allowing you to cut exactly where you want it, with no burrs or rough edges. Get one on every order. To distinguish between Generation 2 and 3 trimmers, check the underside for a white sticker. The top number on this sticker indicates the version. Furthermore, Generation 2 trimmers feature a single bar holding the cutting blade head, whereas Generation 3 trimmers have a double bar.