The Expo chisel black markers come in a pack of 36. Each has a cap on the top to prevent it from drying out. When the top is taken off, it can be stuck on the bottom side of the marker. The marker tip is angled for thinner lines but can be angled a little differently to have thick lines. The markers erase well with a paper towel or tissue. The Expo chisel black markers would be a perfect option for teachers or students that use a whiteboard frequently.