The Federal Signal Valor is a roughly triangular lightbar in a similar shape to the Vision SLR. Many agencies use it because of its stellar intersection clearing ability, due in part to its triangle shaped design. It is a very low-profile lightbar (roughly 2 inches tall (excluding mounting feet)) but also has Federal Signal Spectralux technology allowing for multicolor LEDs. It is available in 44" and 51" lengths.
Agencies that use it:
The majority of police agencies.
Red, Blue, White, Amber, or a mixture of RWA or BWA. No green or purple sadly.