OLO Markers Discover the world of OLO markers at Stamped Designs OLO markers currently come in 128 colors and are an alcohol-based marker. They use a revolutionary ink cartridge technology and are customizable so that you can get only the tip you want and not be forced into a full-size pen with a tip that you rarely ever use. Stamped Designs sells the brush tip “half pen” which allows you to create a full-size pen with 2 different colors, saving you space and ink. No wasting of ink to a tip that you don’t need. OLO Color charts (in PDF): 128-color chart by number Color chart by color family Fully customizable markers The ink cartridge system is more efficient than the traditional felt wick system used in many pens. Refilling your OLO markers is a breeze – you simply purchase a refill cartridge and remove your nib from your existing marker and put it in the refill cartridge, then cap it with your colored cap. No bottles of liquid, no mess. Less storage space. Stamped Designs has the full rack of refills for every color available. Reasonably priced and simple to use.