Columbia Cleanroom 700-9594-BLA Black cleanroom dry erase marker, chisel tip - 12/CSColumbia Cleanroom 700 9594 BLA Black cleanroom dry erase marker, chisel tip 12 CS Black chisel tip cleanroom safe, Class 10 dry erase marker. Our Cleanroom Dry Erase Whiteboard markers are Class 10 certified and are made with an alcohol base for low odor. These dry erase markers work on whiteboards and most non porous surfaces. They come in packs of 12 and are double bagged. The ink can be erased without solution using a dry wipe.