Monroe M33X Super Saturated Black/Red Printing Calculator Ribbon Cartridges
 
The M33X cartridges produce the darkest printing black/red colors on the market, thanks to Monroe's exclusive True Red™ color. Unlike other brands, Monroe's True Red doesn't have an orange tint, providing you with a rich, vibrant color every time. The M33X cartridges have the highest possible inking degree, ensuring virtually smudge-free results. For the darkest print, it's recommended to change your Monroe M33X ribbon cartridges after replacing 2 paper tape rolls.