Mildliners are double tip pens. One for overlining and the other smaller for details. Very nice and gentle colors. Good format for pencils to fit in pencil cases. Faber-Castell in classic design. But here you will find glitter and glamor and pastels. Tombow's Mono edge has double tips but also has a plastic cover on the tip. The aim is to avoid smearing the ruler! Super smart solution and also in a good format for the pen case or pen cup. Erasable highlighting pens can be found in Pilot's FriXion assortment. Good if you want to resell a course book. Finally Spotliter VW that has double tips with different colors. You get 2 colors in one and is perfect in the pencil case. They all have something out of the ordinary!