Collins CM-631 UV Invisible Blue Bulk Pack - 2 x QD & 1 x Bottle
The CM631 invisible blue ink is an invisible ink that is only visible under an UV light. Designed to be used on both offset and coated stocks that do not have optical brighteners. For stocks that do have optical brighteners please see the Collins TWW1929. This CM631 invisible blue ink cartridge is ideal for security and insert/envelope matching applications.