Model Number: N2 cartridge Brand Name: DN Key Specifications/Special Features: These CO2 cartridges are widely used with fire extinguishers, there are two types, one is internal cartridge, and one is external cartridge SIZE55G75G 120G 150G ITEM NO. DN30-01 DN30-02 DN30-03 DN30-04 OD 28MM 28MM 35MM 35MM VOLUME(ML) 74 110 160 200 CO2 FILLED WEIGHT(G) 55 75 120 150 CYLINDER LENGTH(MM) 208 267 255 305 TEST PRESSURE(BAR) 290 290 290 290 MIN WT(MM) 1.5 1.5 1.7 1.7 MATERIAL ST52 ST52 ST52 ST52