Yes, I wonder about the safety issues as well. Although, the guy at fancy steel seems pretty knowledgeable.....as does the guy on this website.

https://www.discerningspecialist.com/bdsm-gear/restraints/52-dsg-leather-shock-collar

I know about the whole "no electrical play above the waist thing" to avoid the charge inadvertently passing through the heart but I wonder if having the two contacts so close together makes a difference?

In any event, I think one that could be properly secured on the balls so as to be irremovable and that was capable of delivering a debilitating shock would be the best option.....and more in keeping with the D/s-BDSM vibe smile