This high pressure acid digestion vessel with a 23 ml, PTFE cup and cover in a strong outer body is either made of stainless steel or nickel.

Stainless vessel is ideal for use with nitric, sulfuric or other oxidizing acids, offering high resistance to any acid vapors which might migrate through the PTFE cup under high pressures. Working pressures up to 5000 psi and temperatures to 275 °C can be handled. Stainless vessel has a safety blow-off disc which will release through a passage in the bottom of the vessel.

Vessel with a nickel body is to be used with HCl, HF and other reducing acids. Pressures in the nickel vessel is limited to 3300 psi due to the lower physical strength of nickel. The nickel vessel does not have a blow-out passage since reactions with reducing acids are not potentially explosive.

Extreme pressures developed in these vessels will tend to deform the PTFE cup, making it difficult to remove the cup from the vessel. To overcome this problem, spanner jack can be used that will push the cup out of the vessel with a smooth, uniform pressure without damaging the cup.