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The first one will probably be so flimsy as to be useless.
The metal one will be no good for long term wear, but fine for messing around and experimenting. Do however make sure you get the right length!
You might have more luck with one of the Holy Trainer clones: http://www.amazon.com/Nice-Opple-Male-Chastity-Device/dp/B01EH39MTU/ref=pd_sim_sbs_236_7?ie=UTF8&dpID=412iwgXGINL&dpSrc=sims&preST=_AC_UL160_SR120%2C160_&refRID=1Y22220XBJ1EH48CC1KA