The icon resembles a traffic cone with a rounded top instead of a sharp top. It has a slim rectangular base and looks like an upside-down cup. There are six short lines evenly spread out and emanating from the cone that are intended to give the impression that the siren is making noise or flashing.
This is a Siren icon. It is available in PNG and vector. Downloading is free for PNGs up to 100x100px.