http://dustinlee.ca/power-bar-01/ 
http://thmiii.com/?p=60 SS-70H – Flush Mount Self Contained Siren
- High impact white ABS housing
- Two-tone, yelp and steady
- 6-12VDC operating range
- 350mA current
- 110dB (steady) 110dB (yelp)
- 18 cycles / 5 sec sweep circle duration
- 6.25″(L) x 5″(H) x 1.5″(D)
- Tone: steady or yelp (wiring selectable)
