A snoot and honeycomb helps direct light to the area where you desire. With the honey comb in place, the light beam becomes narrower and less intense, which is ideal for portrait and product photography. Use of a snoot will result in a small circle of light, when it is attached to the front of your light source. The size of the circle of light will be determined by the opening of the snoot, its length, and the distance of the subject.
A grid spot attachment is a device that has an inch or so of honeycomb metal mounted into a frame that attaches to the front of your studio flash unit. The purpose for the honeycomb material is to collimate the light into a narrow beam. There are different sizes of honey comb material where the individual holes vary from about an a tenth of an inch up to a quarter of an inch. The narrower the hole the narrower the beam exiting the flash unit. At a distance of 10 feet, a grid with small holes in the honeycomb might project a pattern of light no bigger than 10 inches or so. A grid with larger holes in the honeycomb will be a bit larger.
Grid spots are also useful when you wish to add a small splash of color to the background in a very specific place. Simply added a color gel and point the light where you want it. It is important to use a grid that has a flat metal frame around the front so gels can be easily clipped on.