The Universal Twin Spool Calculator Black Red Ribbons 4 Pack by Porelon is a set of replacement ribbons designed for use with a variety of calculator models. Each ribbon comes in a double spool for extended use, with a total of 6 double spools included in the pack. Made in the United States, these ribbons are compatible with universal calculator brands and feature a black and red color scheme. With dimensions of 6" in height, 5" in length, and 1.5" in width, these high-quality ribbons ensure accurate calculations and printing.4 new ribbons