Handle for MMU3 Access Panel on Coreboxx

This is a small handle to replace the hole in the Coreboxx MMU access panel.  Make opening the door much easier and seals up the hole if using the Semi-smart heater. Printed in PETG with 0.4 nozzles default settings.  Two versions of the handle are provided one for M3 x 4mm inserts and one to attach with bare M3 screws.