The V5 series is characterized by a traditional round chamber. These mouthpieces are available in a wide variety of models that suit classical and jazz musicians. The A25 model is very similar to the A15 but a little more open. Vandoren recommends that players use reed strengths between 2.5 - 3.5 with this model mouthpiece. Instrument: Alto SaxophoneOpening: 1.86mmFacing: Medium LongSeries: V5