Hello Mistress Simone-
I would have to say that the medical devices I enjoy most are sounds and anal specula. Like many others, being invaded and probed is a large part of what makes medical play seductive. I also really enjoy the potential for progressing to larger objects as we go. Knowing that the speculum can always be opened up just a little wider, or that there's always a bigger sound lying on the tray is thrilling. I both crave and fear being stretched that next inch.
Uniforms have a pretty powerful effect on my mindset. And for me the classic nurse's uniform represents and projects authority, intelligence, sexiness, and that aura of "I'm a professional and I know what's best for you," which combine to put me in a lovely head space. Also, many of our medical visits in life happened because someone else made us go. Whether a parent or spouse, a boss who sent us home from work, or the medical secretary who called and chastised us for being overdue for a visit, "going to the doctor's office" is already a kind of submissive act. Even before you walk in the door. And that's pretty fun too.