Early this year an instructor came to show us how to use our quilting tools and she said that every company has their own way to mark the rulers and that we should all have rulers from the same company. BUT you must check and make sure the lines are all the right distance apart and that the lines are straight. She told us of one lady in a class she was teaching who was having problems,so the teacher checked the new ruler(Bought for this class) and found the lines on the ruler were all over the place hence the problems. With this I like to let EVERYONE know the story and ask you 2 things. Make sure all the rulers are from the same place and check to see if they are measuring the same and and are straight. Also the rulers with the THINNER lines are the best.