This type of simple wire trap has been used for a long time in France, nearly a hundred years, and were colloquially known as 'Aurouze' traps after the Paris manufacturers of that time. I have not used them, but I have handled many different versions over the years and find that the temper leaves the copper ones faster than the iron ones, and that they can be improved in use by the addition of a flat round washer with small cut outs at the edge in place of the wire square 'setter'. This can be attached by means of a small string or wire to the trap so it is not lost.
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