Bought two of the crystals, measurements show low technical tolerance! UH has cheaper crystals, but these coronas have a really fair price, according to the data. Measurements show all data within boundaries!
But be aware: This crystals have a lower capacitance ( 7nF!) than other crystals. Futaba crystals are good, but they have a higher capacitance. So I would always use the corona crystals for the corona receivers!
Most people are reporting only good statements about the corona receivers, but some report about problems like glitches. Maybe they better should have used original corona crystals?! -)
Conclusion: A few cents dearer then the cheapest crystals you can buy, but definitely better and worth of it and really a fair price! If you use a corona receiver, you will be satisfied with the original corona crystals.