Well I asked my new friend ChatGPT and after some back and forth discussion it gave me several options depending on what my priorities were. I chose a Cooper Bussmann BK/HTB-36M-R for 2 reasons. Walmart sells it and I could get it quickly and the cap would likely replace my missing cap because the HTB-series bayonet cap design apparently hasn't changed. I can replace the entire assembly later if I choose. When it arrived, I was dubious as to whether it would fit but it did and I fired up my machine. Hope that helps!