L21
L21
The Whelen L21 beacon offers high-intensity, 360-degree light output, perfect for utility and construction vehicles. This beacon is engineered to perform under the toughest conditions, including harsh weather and heavy-duty environments, making it a reliable solution for vehicles that need superior warning power. Available in high and low dome models, the L21 is easy to install and offers multiple flash patterns to meet various operational needs. Its advanced Super-LED® optics provide consistent light output, while its rugged construction guarantees thousands of hours of continuous use. The L21 combines durability and performance, delivering long-lasting warning protection to keep your vehicle visible and safe on the road.

Features
- Multiple Dome Options: Choose between high-profile for maximum visibility or low-profile for a sleek, compact design
- Long-Lasting Performance: Rated for thousands of hours of reliable operation
Specifications
Please note: Not all specifications will apply to every model. Consult your sales representative to confirm specs.
Optics | Super-LED® Beacon |
Technology | Scan-Lock™: Advanced flash pattern control Sync: Connect multiple Whelen devices for synchronized or alternating flash patterns |
Flash Patterns | Permanent Mount Models: 25 Scan-Lock™ flash patterns Magnetic Mount Models: SignalAlert™ 75 |
Control | SmartLED® |
Customization | Dome Profile: Low or High Optional Additions: Branch Guard, Mirror Mount Bracket, or Shelf Mount Bracket |
Construction | Hard-Coated Polycarbonate Dome: Resists environmental damage from sand, sun, salt, and road chemicals Polycarbonate Base Fully Encapsulated: Moisture, vibration, and corrosion resistance Reverse Polarity Protection Minimal RFI/EMI Radiation: Virtually zero radio frequency or electromagnetic interference Durable: Rated to last thousands of hours |
Mounting | Combination (Permanent/Pipe/”J” Hook), Magnetic, or Magnetic/Suction |
Included Cables & Hardware | Permanent: 18 AWG 15" (38.10 cm) Pigtail Magnetic, Magnetic/Suction: 10' (3.05 m) Cigar Cord |
Certifications | SAE Standards SAE J595 SAE J845 Regulatory Compliance R10 |
Warranty | 5-year |
Voltage | 12/24 VDC |
Amps | 12 VDC: 1.5 (peak), 0.6 (avg.) 24 VDC: 0.75 (peak), 0.3 (avg.) |
Size | Low-Dome Height: 5.31" (13.49 cm) High-Dome Height: 6.81" (17.30 cm) Diameter: 6.44" (16.36 cm) |
L21 Series Super-LED® Encapsulated Beacon
Amber or White, Perm/Pipe/"J” Hook Mount, High-Dome
L21H*M
Amber or White, Magnetic Mount, High-Dome
L21H*V
Amber or White, Magnetic/Suction Cup Mount, High-Dome
L21H*P4
Amber or White, Perm/Pipe/"J” Hook Mount, High-Dome, 24 VDC
L21L*P
Amber or White, Perm/Pipe/"J” Hook Mount, Low-Dome
Amber or White, Magnetic Mount, Low-Dome
L21L*V
Amber or White, Magnetic/Suction Cup Mount, Low-Dome
L21L*P4
Amber or White, Perm/Pipe/"J” Hook Mount, Low-Dome, 24 VDC
Options
Mirror Mount Bracket for L31 / L32 / L21 / L22 / L10 Series Beacons
BBKT20
Shelf Mount Bracket for L21 / L22 / L10 Series Beacons, Stainless Steel, Mounts to Flat Vertical Surface
BGL
Branch Guard for Low-Dome for L21 / L22 / L10 Series Beacons
BGH
Branch Guard, High-Dome for L21 / L22 / L10 Series Beacons
MMK
90 Lb. Pull Magnetic Mount Kit, with 8' Straight Cord and Plug for L21 / L22 / L10 Series Beacons
LSK
Single Lighted Switch (15 Amp Rated), Mounted on Bracket, Wired and FUsed
DH2000*
Replacement High-Dome for L21 / L22 / L10 Series Beacons
DL2000*
Replacement Low-Dome for L21 / L22 / L10 Series Beacons