For anyone experimenting with frequency doubling /tripling of fundamental frequencies I have a good used LBO non linear crystal 3 x 3 x 16.5 mm on Ebay as well as a 30KV @ 0.02 uF CAP great for Tesla coils, rail gun, HV power supply, etc....
See " http://tinyurl.com/29p7u8 "


Good luck bidding.
Rick