There is provided an adaptor (40) for forming an electrical connection between a medical device having a first type of connector and an electrode having a second type of connector. The adaptor comprises a first connecting part (42) shaped to cooperate with a corresponding connecting part on one of the medical device and the electrode so as to form a mechanical and electrical connection therebetween. The adaptor (40) further comprises a second connecting part (44) comprising a portion of magnetic or ferromagnetic material (46) arranged to be magnetically attracted to a corresponding magnet or portion of ferromagnetic material comprised in a magnetic connector part on the other of the medical device and the electrode, so as to form a magnetic and electrical convection therebetween. The first connecting part (42) is electrically connected to the second connecting part (44).
