From the official site:
Since 1953 Grado Labs has adapted at our own pace, and the first wireless Grado headphone is only the first step in what’s to come. We took our time to get the sound just right and made no compromises in the GW100. Nothing is lost except the wires.
Inside the GW100 are none other than our signature Grado drivers. These speakers are the same ones we build for our wired headphones, which are finely tuned for the different enclosures we use. Grado Labs' first wireless headphone is no different, with drivers configured specifically for them. The desired sonic capabilities of the GW100 would not be possible without decades of experience in driver design.