Dritz Marking Pen 2-Sided Blue and Purple for quilting and crafting

I mark my quilt with lines to help me keep my ruler quilting straight. I do not have a longarm but I mark the lines on my quilt sandwich using gigantic stencil grids I got from longarm university (link below). I use Dritz Dual Purpose Twin Marking Pen to mark the lines. I use the blue end (removed by water) unless I'm absolutely sure I will quilt on those lines that day. The purple end is removed by the AIR in 24 hours. Stencil Grids: https://www.longarmuniversity.com/MQ-Templates/Grid-Stencils.html Marking pen: https://www.walmart.com/ip/Dritz-Dual-Purpose-Marking-Pen-Blue-Purple/24592207