Discontinued sampler
Simplex 2000
The oldest version, Simplex 2000, not more produced since 1998, but you get always.
Simplex 2200
Simplex 2200 the most only one which closed against the pipe presure. Not more produced since 2001.
Simplex 2500
Simplex 2500 previous version of the Simplex 2500. Not more produced since 2007.