This is so useful for anything you work from line-by-line instructions. Featuring the Ginger Twist Studio Kitty, this tracker is designed for knitting when the pattern is laid out as a chart (especially useful colour work) and can be used for written out patterns too. It's also great for cross stitch and in fact any instructions you follow line by line.
Sandwich the instruction sheet between the front and back of the tracker, and move it up the sheet as you go. The top ruler is made from clear acrylic (recycled of course!) so you can see the line you're on and - here's the game changer - the line you've just completed as well. When you work from a chart you know that the line below is Very Important Information, as a reference to make sure you're working in the right place.
If you have a large pattern sheet and want a bigger base, the top part works on anything which attracts magnets.