Description Literature Description Freudenberg Sealing Technologies (formerly Tobul) poppet spring used with TRBT30 and TBR50 Bladder accumulators returns the valve to the closed position within the valve stem to maintain an air-tight seal by forcing the valve to the valve seat. The poppet spring accumulates kinetic energy during the contraction and the energy is dissipated upon expansion. State of California Proposition 65 WARNINGCancer and Reproductive Harm - www.P65Warnings.ca.gov. Literature & Docs Accessories