Battery Lock Knobs.

[Surely Bassey]

Hard to find. They are available

lok-knobs.com

These are great

 

[Fishtales]

I guess if you're doing a lot of connecting and disconnecting or if access is a problem. Really not needed in my set up.

 

[seasick]

I looked at those and my first thought was that if you use them, you cant cover the positive terminals with a non conductive cap as required by ABYC regs.

 

[Surely Bassey]

Actually you can cover the terminal if you wish.
I like the safety factor of covering the stud. Once I was using a socket wrench and touched the other terminal. Very scary.

 

[seasick]

I sort of get your point.
The ABYC regs require that all positive terminals be covered so that means both the post and if present the threaded terminal. In your picture, that is not the case but I am sure you didn't mean to say that the knob alone was enough.
I could see an advantage of the knob for batteries that are removed often, whatever that means. Perhaps some folks pull trolling batteries and charge them out of the boat.

 

[Doc Stressor]

Those rubber terminal covers are a joke. Most won't fit on the terminal with the main cable connected. Lok-nobs do at least as good a job of protecting the terminal.

I use lok-nobs on my RV batteries and they hold up to a lot of vibration. I may get around to putting them on the boat batteries one of these days.

 

[Surely Bassey]

agreed.