Can/should I change the O-rings on my jacketed lab reactor piston? Part numbers? O-ring materials have been specially selected, but all O-rings will deteriorate with use over time (through use at low/high temperatures, abrasion/stress from chemical residue/particles, and contact with chemicals). It’s important to regularly check the O-rings on your Reactor-Ready, Duo, Pilot or Lara piston (bottom outlet valve) and replace as required, to prevent any significant leaks. Piston O-rings are FEP-encapsulated silicone as standard. For Reactor-Ready Pilot, the top two O-rings are also available in Chemraz, which is recommended if working above +150˚C. The white piston itself should also be checked and replaced if required. The part numbers and descriptions for the pistons and O-rings are as follows: Reactor-Ready, Reactor-Ready Duo and Lara pistons are 15 mm; Reactor-Ready Pilot pistons are 25 mm. RR161100: Piston 15 mm for Single Jacketed Vessel RR166055: Piston 15 mm for Vacuum Jacketed Vessel RR166070: Piston 25 mm for Single & Vacuum Jacketed Vessel RR166100: Replacement 15 mm Piston Top O-Ring RR166102: Replacement 15 mm Piston Middle O-Ring RR166104: Replacement 25 mm Piston Top O-Ring (Pack of 2) RR166106: Replacement 25 mm Piston Middle O-Ring RR210074: Replacement 25 mm Piston Top O-Ring Chemraz 0°C-230°C (Pack of 2) Standard O-rings are also available as part of the Maintenance Kits. RR121150: Reactor-Ready Maintenance Kit RR210100: Reactor-Ready Pilot Maintenance Kit LR199010: Lara Maintenance Kit