The 1109A is an oxygen combustion vessel developed by Parr Instrument Company. It is specifically designed for small samples like in marine biology or ecological studies. This vessel may also cater other applications wherein there are space limitations. It has a volume capacity of 22 mL even with its small size. Furthermore, it can handle samples that range from 25 mg to 200 mg. It liberates 52 to 1200 cal when burned in oxygen and uses at most 35 atm.