These are Whelen's new Super Linear 400 Series lightheads.  They feature 5 built in scan-lcok flash patterns and are synchronizable with other Whelen lightheads.   They offer a versatile size ideal for bumper, step, or grille mounting. 

FEATURES

• 400 Series are easy to operate and easy to install, simply choose the light source then pick the mounting style.
• High intensity warning
• Soldered-in strobe tubes and improved gasket material assures greater vibration and moisture resistance
• Strobe tubes are parabolically centered within a highly polished reflector for maximum light output.
• Linear strobe tubes carry a two year Gold Medallion warranty
• Furnished with 15' of 3-conductor shielded cable and Amp Mate-N-Lok® connectors (requires a strobe power supply, purchased separately)
• Optional mounting configurations meet all your specific needs: chrome-plated or black polycarbonate flange; rubber grommet; pedestal/swivel mount. International intersection housing also available.
• Available in all 5 safety colors
• Mounting options are purchased separatelyCertifications:
• KKK 1822-E
• Federal Ambulance Specification, Lower Zone Only
• CAC, Title 13, Article 22 (red, blue and amber lightheads)
• SAE J1318  Gaseous Discharge Warning Lamp for Authorized Emergency, Maintenance, and Service Vehicles (May 98) Class 1, Class 2, Class 3