We pride ourselves on our ability to provide exactly what our customers want. As the first company to add sound files to our products online so customers could hear the bowls, we understand the search for the perfect frequency. The 528 Hz frequency has come up in recent years as a popularly requested tone for bowls. Using A=440hz tuning, this puts 528hz in the 5th octave, in our system, a C# in note, about 15-20 musical cents on the plus side.
In our inventory we generally see the 5th octave only in the crystal bowls. In the Classic Frosted, HQ, and Empyrean style bowls the tone will occur in bowls from 8-10 inches in diameter, with the 10 inch size being the rarest. In the Clear Quartz, Featherlight or One Piece Handle style practitioner bowls we only see that frequency in the 5" and 6" sizes.
We update our inventory daily, though we tend to sell bowls that are 528 Hz rather quickly once they are online. To find 528 Hz bowls on our site use the search bar at the top right of the page and search for 528 Hz. Check our Solfeggio tones page here. Additionally the bowls may be found by using the above-mentioned sizes. in the C/C# note for instance 8" here, and then look for the bowls marked 528 Hz.