I use the Quilter's Slide Lock. There is no way I'd use a rotary cutter without a safety tool that keeps the ruler steady. All it takes is one slip for a nasty cut. I don't take the Slide Lock to classes, everyone wants to use it (but too cheap to buy one) and it's hard to keep up with who has it so I use a cut resistant glove when I'm away from home in case the ruler does slip.