Larger bores were popular during the first half of the 20th century. For those players who enjoy the great flexibility of these designs ,Rossi offers the following :

• AL

 15 mm. is the bore diameter currently used in Vienna. This model tunes with a standard French type mouthpiece. Big tone, very flexible and rich-sounding. Barrels for A = 440 and 442 included. Shorter or longer barrels also available. 

• 15.2 mm bore Boehm System, English Model

The English model is based on a pair of 1010 clarinets from 1938.
Ideal for those who follow the traditional English school. This model tunes with  a  rebored  mouthpiece.
Preferred by renowned musicians such as Valdemar Rodríguez (principal clarinet of the Simón Bolívar Symphony Orchestra of Caracas), Jane Ellsworth (Professor of Music at Eastern Washington University), and British soloists Gervase DePeyer and Colin Parr.

• 15.2 mm bore Boehm System, Koktan Model 

Inspired by pre-war instruments made by Koktan in Vienna , this model is unique in that it features the Boehm key system. It features shorter barrels to compensate for its comparatively long body (as compared to the English Model). Produces a rich, focused sound. Used by Luis Rossi for his concerts and recordings. This model tunes with a rebored  mouthpiece.