Last I knew Atichson replaced all of their old sirens (Thunderbolts and 2t22s) with 2001s and Eclipses, but apparently they kept the old sirens in place as some sort of backup. In this video you can hear 2t22s and 2001s, and around 2:15 I think a Thunderbolt 1000.
http://youtu.be/P-uMtM59rKg?t=1m35s