The Federal Signal folks were very helpful. Here is the contact info:
s.tennant@nasig.com
Scot P. Tennant
Director - Sales & Marketing
North American Signal Company
605 S. Wheeling Road
Wheeling, IL 60090
Toll Free: 877-246-6274
Local: 847-537-8888
Fax: 847-537-8895
www.nasig.com