Dremel, since purchased by Bosch, has discontinued producing some on/off replacement switches for some Dremel rotary tools manufactured over 25 years ago.
Kauffman Family Tool had 2 NOS switches in stock and emailed images of both to confirm their correct application. From where I'm sitting no other online company carried this particular rare switch.
Kauffman Family Tool runs an essential business the way most American companies used to operate long before computer algorithms changed the business model and eliminated the emphasis on customer service.
Suffering the humiliation of dealing with a dehumanizing monolith like Amazon is no longer required. Kauffman Family Tool Repair now has that power and it's doubtful Amazon will ever come close.

I conducted a Google search for an obsolete service repair part and found Kauffman. Kauffman Family Tool Repair was very helpful even to the point of giving helpful suggestions on ordering the proper items