This box of 6, 16 gram CO2 cartridges is to be used with our newest QUANTUM series of PATTI adhesion testers. These units include the PATTI QUANTUM Analog, QUANTUM Digital, QUANTUM Concrete and QUANTUM Gold. The CO2 cartridges allow for maximum portability of the PATTI system by eliminating the need for shop air. Please contact us if you are unsure of the CO2 cartridge size of your instrument.