Can I replace the O-ring between my jacketed lab reactor vessel and lid? The part number of the O-ring between the vessel and lid, which is held in place by the white PTFE collar, for Reactor-Ready, Reactor-Ready Duo and Lara is: RR121090: FEP Encapsulated Silicone Vessel O-Ring – DN100 For the larger Reactor-Ready Pilot, it is: RR210022: FEP Encapsulated Silicone Vessel O-Ring – 200 mm All O-rings are considered consumables (to be replaced as required), and they are included in the respective maintenance kits: RR121150: Reactor-Ready Maintenance Kit LR199010: Lara Maintenance Kit RR210100: Reactor-Ready Pilot Maintenance Kit The FEP outer of these O-rings has excellent chemical resistance and the silicone inside gives flexibility. Nonetheless, if you would like to try an alternative O-ring material, we offer the following alternatives for the small DN100 size: RR139103: Viton Vessel O-ring Seal – DN100 RR139105: Isolast Vessel O-ring Seal – DN100 RR139107: Chemraz Vessel O-ring Seal – DN100