https://www.amazon.com/dp/B00AX49A40/ref=cm_sw_r_sms_apa_i_iXaZCbT280T4J

Apparently these are the best you'll find. Under the Q&A section someone details the metals used. What sucks is that about 2 years ago these were on Amazon for less than $20. It might be a good thing if they started using quality metals. I really don't know for sure though.