ROTH Metal detector. Need info on it please

[padlock]

I picked this up at a sale yesterday. I am unable to find any info on it and what it might be worth. Any help with be great

here are some photos of it

It takes 1 nine volt but I have to get some as i dont have any to test it yet. Will update if it works

Enjoy

[diggummup]

That's a tiny little thing. Can't find much other than-
http://forums.whiteselectronics.com/...metal-detector
Nice wall hanger!

Edit- I did find an article in "Treasure" magazine that helps date it at least.

Vol. 1, No. 3, October 1970
"Treasure Product Test - Roth Detector Model 436, "The Colonato""

http://www.workmansbooks.com/Magazin...100411479M.htm
but you have to buy the magazine I guess.
Nice cover shot!