The replacement siren for the Thunderbolt.

[thewoog34]

I'm not so sure. I see a lot more 2001's around than 508's.

That's because the 2001 has been out since the late 80s early 90s. The 508 didn't come out until 2012-2013 I think.

The 508 came out in late Spring of 2012. I specifically remember being on a vacation to Washington DC that summer and the hotel having crappy Wi-Fi so I couldn't watch the first videos of the 508 in the wild.