Momoi escape proof snap

[Kemo Sabe]

Saw this in SWSportsman and it appears to be a way to avoid having to retie jigs or having to store jigs with hooks attached.
Anybody have any experience with these ? Not sure they could be trusted as I don't get many chances a season but thought I would ask.
sarge

[stripernut]

Looks like a rip off of McMahon Snap Swivels. Used them for years, but I did have one or two let the line slide up in between and out. Not on fish, I was jigging.
Did you get to play with them? Was it just the pressure of the line that keeps them closed? Or was there some type of spring action holding them closed? If it is just the line, I would not use them... I am sure they would hold on the pull of the fish, but with the action of a jig or the jerking of a lure????