The Tobul 067A25-40-6216 is a hydro-pneumatic, piston-type hydraulic accumulator rated for 2500 PSI maximum working pressure, built by Tobul Accumulator, Inc. (now operating under Freudenberg/FST). Piston accumulators store energy in compressed nitrogen acting against a low-inertia aluminum piston that separates the gas charge from the hydraulic fluid, allowing the unit to supplement pump delivery, absorb pump pulsations, cushion hydraulic shock, and maintain system pressure during demand spikes or power loss. Tobul's piston design is used in over 90% of accumulator applications and serves industries including oil and gas, power generation, chemical processing, pulp and paper, basic metals, and mobile and aviation ground support equipment.

The model code breaks down as follows: 067 is the 6-3/4 inch (6.75 in) nominal shell diameter, A denotes both heads threaded which is Tobul's repairable (rebuildable) construction (versus "AL" fully welded or "AT" partially welded), and 25 is the 2500 PSI maximum working pressure class. The -40 segment is the fluid capacity/length designator for this family, and the -6216 suffix specifies the port and configuration build. The "BUNA-N" and "-20 to +200" callouts in the listing identify the standard Nitrile seal compound and its operating temperature window in degrees Fahrenheit, which is Tobul's catalog-standard service range for Buna/Nitrile seals.