For anyone looking for a similarly sized unit for cheaper, here's one that closed with no bidders. Just shoot the seller a message and ask them to relist it with buy-it-now price of your choosing: https://www.ebay.com/itm/292985470017Also an ebay find for around $80. I too used to use the Chinese eprom eraser that many have used- just didn't cut it. Keep your eye's open on ebay for these type- they are workhorses.
I've had great luck with them too. Had the same one for over 5 years, never a problem. Recently snagged a much much larger one cheap on eBay and passed good old China off to a friend.I have had good luck with my cheapo chinese eraser. I clean the chip windows with IPA first, and give it a good 20 mins. Almost always works, but I'll still probably upgrade some day.
I'm sure it doesn't really matter but if you're using sunlight, and want to speed up the erasing, try and not have them behind glass. UVB is almost completely blocked by glass, and UVA only makes it through ~75%.I literally have three 27c160’s in my window right now getting some sun lol. My cheap Chinese units bulb burnt out. Never bought another.