Posted: Wed May 14, 2008 8:15 pm
Here's another update. Lea Ann at Rohm and Haas just sent me an email saying that she found out that their Whelens are WPS 2900 series sirens. That means that they must have been made after the pitch was razed from 450 HZ, but before it was razed again to 560 HZ. She plans on sending me pictures of both of the Whelens soon, so you guies can help me determine the exact models.