My laser is working fine but I scratched the focus lens cleaning it. It seems to work fine but I would like to have a spare in case I totally trash it next time I clean it. I see lenses for sale on ebay for 16 bucks shipping included. How do I choose a lens comparable to what I have now? I assume it's a domestic product from China. Same with the mirrors... I suspect I will be no less ham fisted when I clean those.
Adrian