Spotlights are an essential in stage lighting. The ERS, or ellipsoidal reflector spotlight, was developed in the 1930s and remains a staple for productions. Often known as the LEKO from the names of Levy and Kook who designed one of the first versions, today the most common implementation is the Source Four. There have been many adaptations of the ERS principle for photography, designed to attach to the front of studio strobes or more recently continuous lights. The Neewer Optical snoot is one budget version which I have tested here. I also explain the principle of the ERS.