A snoot is a cone-like tube, most often made of some kind of metal, like aluminium, that can be mounted in front of your studio strobe. It will narrow the light so it will be like a spot of light hitting the background, - that is the way I like to use it. I have mine from Amazon, and they have a wide variety to pick from, but quite similar. You will though be able to find some of different sizes. Most are shipped with a set of gels, for making colourful effects using the strobes. Also with the snoot usually comes a honeycomb grid. My snoot can be mounted on the strobe with the Bowens type mount. There is a big selection of studio light modifiers and other equipment that use this standard.
Be aware, what type the mount is, when you go shopping for studio strobes, and light modifiers in general.