My late husband was a ham. His club handled shortwave in our area during 9/11.
He repaired antique telegraph keys and invented and produced, in his basement workshop, the portable miniature key referenced below.
I'll admit I never got it, but he was a very smart man and he loved it. I went with him to many a Hamfest (basically flea markets for ham radio enthusiasts) where I rarely knew the purpose of any of the dooflickers and thingamabobs.