The following products have been discontinued:

LaserGas I SP

Introduced in 1995
Discontinued in 2009
Still supported and serviced
Replaced by LaserGas II SP and LaserGas II SP Compact

LaserGas I DP

Introduced in 2000
Discontinued in 2007
Still supported and serviced
Replaced by LaserGas II SP with zero/span option 

DM3 Dust Monitor

Introduced in 1995
Discontinued in 2006
Still supported and serviced
Replaced by LaserDust MP, LP, and XLP