Information gathered from the internet below: BEST BRASS has developed a unique multi-length system, achieving stable intonation regardless of cup size or depth. It provides a sound as if the instrument has been upgraded. It will also likely resolve issues such as difficulty in hitting high notes and unstable low notes. 【Features of the Groove Series】 ■ Multi-Length System Conventional mouthpieces have the same overall length even when the cup size changes, leading to variations in intonation. BEST BRASS makes the overall length longer for shallower cups and shorter for deeper cups. As a result, accurate intonation and efficient resonance are achieved. ■ Groove Processing Efficiently vibrates the lips, resolving issues such as difficulty in hitting high notes and unstable low notes. As a result, it becomes less tiring to play during performances. ■ Cornet Mouthpiece ■ Groove Series ■ Gold Plated ■ CR-7B ■ Overall Length: 65mm ■ Rim Inner Diameter: 16.250mm ■ Cup Depth: Slightly Deep ■ Throat Diameter: 3.78mm ■ Backbore: CR-L ■ Compared to other brands: Slightly smaller than Bach 7A