The Fisher ® 2625 or 2625NS volume booster is used in conjunction with a Positioners on a throttling control valve to increase stroking speed. The 2625NS is a nuclear-service version and uses elastomeric components that better withstand high temperature and radiation environments. The booster incorporates fixed deadband, soft seat construction and an integral bypass restriction to eliminate Positioners saturation problems that can occur.4womenonly with volume boosters that do not have these features.