I bought mine at a quilt show but some fabric shops are carrying them or you can order on line. The smaller size will work for most work but I have both sizes. Get the neon color instead of the clear (I have the clear but wish I had the other). It really doesn't take a lot of pressure--about the same that you would put on a ruler to hold it in place. I use another ruler with it instead of the grid lines, I line up the cut I want to make with the ruler extending to the right (I am right handed) and but the slide lock up to the ruler, press down, slide the ruler out of the way and cut. Hope this helps you decide. I have short arms and as I reach to hold the ruler down it always slips. With the Slide Lock I don't have that problem.