Cuffs worth

I have two cuffs I am looking to sell. Both are in good condition.

Thin model plug eight with original key. Plug was made by a machinist 20 years ago so not original.

Mattatucks with key.

Can you provide me with an idea of worth?

The Mattuck is worth $100 or so depending upon condition.
The value of the plug 8 can not be given without a picture. What markings are on it? How heavy is it?
Post a picture if you can.

Joe