www.canfieldequipment.com
Price: $144.00
Item #: W-2519HPA

2519HPA

Encapsulated, Scan-Lock™ Flash Patterns, Photocell Hi/Low with Hi Power Override. Magnetic Mount with CometFlash® and Hi Power Only.  19 Watt, Perm/Pipe/"J" Hook Mount, High Dome.

See  http://www.whelen.com/_AUTOMOTIVE/details_prod.php?head_id=1&cat_id=5&prod_id=176 for more details.