MRH70A: Spot Color Blue - Compares to HP® C6170A Spot Color Blue & Collins CM Series of Color for Addressing Systems. Spot Color Blue or MRH70A ink is used in single color applications for spot color addressing and packaging requirements. This ink is designed to be used on porous surfaces and should be tested with other formulas in multi-head machines with different inks. MIX & MATCH ANY SPOT COLOR INKS FOR CASE DISCOUNTS.