Eugne Albert made an improvement in Iwan Muller's 13-key clarinet, adding two rings, or brille (glasses), to the lower joint and this resulted in the 13 key/two ring clarinet.
In 1840 he made an improvement in Iwan Muller's 13-key clarinet, adding two rings, or brille (glasses), to the lower joint. This resulted in the 13 keys / 2 rings clarinet. 
