The NU-Calgon 4179-16 is a 12-pack of 16g Mag 16 CO2 Cartridges that are used with the 4179-01 Gallo Gun that function together to clear clogged or slow moving drain lines. It clears a single standard condensate drain line with 800 psi of oil free air. The Gallo Gun should be discharged of any unused gas and the cartridge removed after use, preventing the seals from setting and extending the life of the tool. THE NU-Calgon 4179-16 MAG 16 CO2 CARTRIDGES IS FOR PROFESSIONAL USE AND SHOULD ONLY BE USED IN ACCORDANCE WITH ALL REGULATIONS AND PROPER SERVICE PRACTICES. PLEASE SEE PRODUCT LABEL OR CONTACT NU-Calgon DIRECTLY FOR USE INSTRUCTION. IT IS RECOMMENDED TO UTILIZE THE APPROPRIETE PPE (PERSONAL PROTECTIVE EQUIPMENT) DURING APPLICATION.