INKUTEN Refill Ink Bottles for 664 T664 cartridge Expression EcoTank ET-2500 ET-2550 WorkForce EcoTank ET-4500 ET-4550 (500ml per color) Made in the USA Package Include: 4 Bottles, 500ml/bottle (1 Black, 1 Cyan, 1 Magenta, 1 Yellow) 4 syringes with needles. Cartridge number : T6641 T6642 T6643 T6644 T7741 EXCELLENT INK FLOW - No clogging jets for long jobs and continuous printing Increase productivity through high speed printing SUPERIOR QUALITY - Resists fading, smudging and bleeding with INKUTEN Color technology to allow you to print true-to-life photos and images and laser-quality text which withstand fading for decades. Built to meet or exceed OEM specifications 2 YEAR NO HASSLE WARRANTY - 100% No Hassle Money Back Guarantee with 2 Year Warranty