Although theoretically Thornes' 2nd quality, you'd have to be very picky to see why and the bees are most unlikely to complain. I have made a few of these now and can confirm that joints are snug and consistent and that the wax slots perfectly align to receive your choice of foundation. These are very easy to recommend, especially if you live close enough to collect.
Like the SN4 frames I bought these are good quality and not obviously seconds
Very prompt service and being local it is much easier to get supplies. Only just starting out bee keeping and still learning.