These specially designed tips connect to any slip-type syringe. The purpose of these tips is to suction or prime cartridges including many popular HP, Brother and Epson models, including on OEM and also on refillable cartridges for Epson DTG machines such as the P400 / P600, HP 975, HP 952, HP 954, HP 955 more. The tip is slotted so that while depressing the valve inside the cartridge, flow of ink or air is not impeded. Also work on CISS (continuous ink system) cartridges. When you refill cartridges, air gaps or pockets can form inside the cartridge, causing ink flow issues and the cartridges not to print correctly. These specialized tips allow you to safely and efficiently suction out the air and create a continuous ink flow (also known as priming). Simply attach a tip to a slip-type syringe, and suction some ink out (about 3-5ml), as you suction out the ink, air will also be suctioned out and help create a continuous ink flow in your cartridge or CIS system.