SLIDELOCK RULER They may seem expensive but less expensive than a trip to the ER! Absolutely could not get along without the two I own. The 14" and the 24" lighted edge are the ones I've had for several years now. I have a healthy fear of rotary cutting, after reading several mishap posts on this board. The Slidelock keeps your hand/fingers away from that cutting edge.
http://www.quiltersslidelock.com/purchase/