I’m so happy that I found these Expo 90% Recycled Sidekick Organizer With Markers and Eraser. The 4 colors are bold and vibrant, yet erase away effortlessly when needed. I can use them on my whiteboard and on the job site. They work great on glazed bricks, glass blocks and tiles. I am able to mark my needed dimensions before cutting and then not worrying about having the marks remain permanently.