"hey whelen, how are your collector rings doing?"

this siren is also known as the Whelen Vortex R4. i know, it looks more like the pre 1995 variant.

requested by @Mrcooldude

requires tone generator mod

In 1990, two more sirens would be introduced, the WPS-4000-3 and the WPS-4000-4. These were essentially a WPS-4000 cut in half, with 3 and 4 400 W speaker drivers each, reaching 124 dB and 126 dB at 100 ft, respectively. These lacked the covers above and below the throats, as well as the horizontal strut on the projector. The WPS-4000 itself would be renamed to the WPS-4000-8. Everything else about these two sirens were identical to the WPS-4000-8. Also introduced around 1990 was the WS-404R, which was a tone-only variant of the WPS-4000-4 which lacked voice capabilities and was meant to be a more affordable option.

In 1995, the WPS-4000-3, WPS-4000-4 and WPS-404R would receive a visual overhaul. The mesh screen was moved from the very front of the projector to about halfway inside of it, and the X shaped support struts were removed. The bulges on the sides of the projector were also removed. It was at this time that the WS-404R would be renamed to the VORTEX, with a cheaper 3-driver model being introduced alongside the 4-driver model. Some VORTEX sirens came equipped with a large fin attached to the driver housing, likely to aid the siren's rotation in high winds. This would only be installed on earlier units, with later VORTEXes lacking the tailfin. These are often referred to as "Finback" VORTEXes by enthusiasts.

The VORTEX also received a different rectangular rotator, which lacked the quadrant control and indexing features, and was originally belt-driven instead of direct-drive. Originally it used a very simple rectangular design resembling those used on early WS-3000 units, before later being updated to its current, more complex shape. The new rotator design uses a direct-drive gear driven rotator, which is more reliable than the older belt-driven rotators. This rotator would also be used on Whelen's HORNET siren.

Around 1999 or 2000, the names of the sirens would be overhauled. The WPS-4000-3, WPS-4000-4 and WPS-4000-8 would be renamed to the WPS-4003, WPS-4004 and WPS-4008, respectively. Additionally, in 2002 the VORTEX sirens would be renamed to the VORTEXR series, and a 2-driver model was introduced. In 2003, the WPS-4008 would be discontinued due to costs and lack of sales, as its price did not justify its performance compared to the WPS-4004. The final addition was in 2010 with the introduction of the VORTEXR1, a single driver model of the VORTEXR, with performance matching the HORNET. The WPS-4004 and VORTEXR are compatible with Whelen's VisuAlert visual warning beacons.