The Aquarium UV Sterilizer market has now been mostly taken over by
Category C UV Sterilizers which are not capable of level one or two
sterilization unlike 'Category B' or especially 'Category C' units.
HOW DID THIS HAPPEN?
While these cheap UV clarifiers masquerading as true UV Sterilizers have been around for some time, misguided Obama regulation outlawing high output magnetic ballasts in 2014, has made just obtaining a UV clarifier that can fire the High Output UV lamps capable of running a 'Category B' or especially 'Category A' UV Sterilizer difficult to find if at all in some size UV Sterilizers.
In depth UV Sterilizer information:
Aquarium Pond UV Sterilizer Use; Facts & Information
The reason for this law was for efficiency of fluorescent lights,
which is fine for your average hardware store fluorescent light fixture,
but NOT for a high output UV Sterilizer.
This law opened the door for even more cheap Chinese UV Clarifiers masquerading as true UV Sterilizer to flood the market.
When one considers the wide price of ballasts and HO UV lights versus low output UV lights, price alone is an easy indicator.
You cannot sell an 18 Watt UV Sterilizer with "free shipping" (which requires the seller to pay shipping) and pay eBay fees of 10%+ for $60 when the actual cost of a true Category B CUV-118 Terminator UV is well above $60 and stay in business.
So obviously these sellers (such as one eBay seller in China operating out of a home Hacienda Heights, CA.) are selling UVs with standard ballasts/power supplies and low output UV lamps, so all you are getting is a Category C UV Clarifier.