The B-flat bass sarrusophone is the bass member of the sarrusophone

Sarrusophone

The sarrusophone is a family of transposing musical instruments patented and placed into production by Pierre-Louis Gautrot in 1856. It was named after the French bandmaster Pierre-Auguste Sarrus who is credited with the concept of the instrument...

 family of metal double reed

Double reed

A double reed is a type of reed used to produce sound in various wind instruments. The term double reed comes from the fact that there are two pieces of cane vibrating against each other. A single reed consists of one piece of cane which vibrates against a mouthpiece made of metal, hardened...

 instruments. It has a range almost identical to a bass saxophone

Bass saxophone

The bass saxophone is the second largest member of the saxophone family. Its design is similar to that of the baritone saxophone, with a loop of tubing near the mouthpiece. It was the first type of saxophone presented to the public, when Adolphe Sax exhibited a bass saxophone in C at an exhibition...

. There are very few pieces written for it, although one of them includes Roupen Shakarian's Sarruso Rex. It is among the rarer of the sarrusophone family, and they were only produced by Gautrot (a company run by Pierre L. Gautrot, who invented the sarrusophone), Couesnon (a descendant of the Gautrot Company), and the Orsi firm, who still makes them as special order items.