Can I buy a replacement Reactor-Ready stirrer drop-in coupling? Yes, the drop-in coupling is available as a spare part. For Reactor-Ready and Reactor-Ready Duo, the part number is: RR121065: Stirrer Drive Drop-in Coupling B24 10 mm For the larger Reactor-Ready Pilot, the part number is: RR121140: Stirrer Drive Drop-in Coupling B34 16 mm Spare parts for the drop-in couplings are also available; please refer to the separate FAQ entry, ‘How do I change the metal pins of the Reactor-Ready drop-in coupling or the stirrer guide cap?’