The L-14A4L has a semi-flat rim. The cup is medium depth, with a rounded entrance to the throat which allows plenty of air flow for a nice big sound. The throat is a #27, but the throat cylinder length has been enhanced. The backbore is a Legends S. Slotting, range and endurance are excellent with the L-14A4L. This mouthpiece is equally equipped for solo, lead or jazz playing, with extra zing when needed.