This is the Artemis 3, made by BEST BRASS, one of Japan's proud manufacturers. It has a 16.85mm inner diameter, and as you can see in the second photo, the throat has a groove. The fourth image is a quote from their website, indicating that this model is the result of the Groove and Groove Kai models. Personally, I felt it had a very pure tone and excellent breath support (like a horn player). However, I feel like the inner diameter doesn't quite suit me, so I'm putting it up for sale. If the size seems right for you, please give it a try! Also, the original box is included. Current retail price: 19,800 yen