Unusual Plug 8 Cuff with Serrated Edge

I just purchased this unusual plug 8 from Mark and Sheila Cannon. It has several novel features. Most notable one edge of the cuff is serrated in a decorative manner. The center of the cuff comes together in a unusual “v” cut. The key has a nonstandard shape and most importantly has three flutes instead of the normal four. The cuff has no markings of any kind.

Does anyone know anything about this cuff?

Does anyone have other cuffs that share these same features?

Please post a reply if you have any ideas.

Joe

Hello there,

Noticed on an original penal colonial set that the trianglular key / lock mechanism is used.

The difference is that it is a perpedicular key rather than longitudinal to the ankle cuff.

Suggest that the Plug 8 were intended for total imobilisation as during transport.

Interesting to note that the same key is in use here in New South Wales today with the traffic light control boxes dotted near intersections. Same with the state railways who use the same triangular key for door access between carriages and guard / driver compartments.

Best of luck with the site.

Harry K