" I agree with you here , if you buy a $10-20 zapper you'll have an inferior product . Thanks for your response!"
I'd like to point out that for $10 spent on a http://www.tendollarzapper.com
zapper, what you get is a very well made item that is EXACTLY the item described by Dr. Clark. The same EXACT circuit that ALL of her testimonials are based on.
Have others improved on this? Probably so, however Dr. Clark appears to get good results using the basic zapper that she gives construction details for. That same basic unit is available for less than the parts (not to mention the time) would cost you AND it will arrive faster than you could collect the parts.