My current design project requires many straight cuts in 145 g/m2 cardstock. Have been using metal rulers for a straight cutting edge but they would often slip while cutting and ruin the part. Discovered this anti-slip ruler from C-Thru called the E-Z Grip 12" ruler, product number MG-12. It has two round elastomeric contacts that allows the ruler to completely touch the paper at the ruler edges while preventing unwanted slips. An added bonus is that it has a convenient T-handle for easy tool manipulation and alignment adjustments. If anyone is cutting many straight edges, I believe that this ruler will make the task really pleasant. It can be found in craft and scrap book stores.