30ml Premium Nano Refill Ink Kit for HP 901, 901 XL, 60, 60 XL, 56, 27 Black Ink Cartridges + 1 instruction World-class Nano-technology! Smell: Normal odor; PH: 6~8; Particles: N/A; Stability: No settling in 3 years (at normal storage); Temperature: -15C no frozen, 70C no gelling; Lightfastness: 5~6 BWS; Waterfastness: 3 (average); Gasfastness: 4 (good); Fast drying time, even on the glossy paper!