T. R. McElroy was a blazing fast telegrapher -- any code, any time. He worked both landline and radiotelegraphy, and set speed records.
But he was ambitious, too. In the 1930s, he started manufacturing semiautomatic telegraph keys of his own design, massive, heavy bugs that suited his own style -- and which appealed to plenty of others, too.
The original Mac bugs were heavy, rectilinear keys with their own style, a little "Arts & Crafts meet heavy industrial" look. But the times --and the styles -- were changing and shortly before WW II, Mac introduced a series of streamlined telegraph keys unlike any any other, culminating in the S-600 Super Streamspeed semiautomatic key, possibly the most graceful "bug" ever made.
I own a few Mac keys and recently bought an accessory:
Restoration will be interesting. The Bakelite is likely to be very brittle.
There are still McElroys in the electronics business. They're not making telegraph keys any more, but the name lives on.
* TACo was a co-venture between McElroy and Hallicrafters. They built copies of Mac Streamkeys and their own interesting semiautomatic key, sometimes known as the "hole-in-the-wall" bug.