A light includes a bottom box, a cover mounted on the bottom box, a light emitting shield mounted on the cover and a back plate; the bottom box includes a bottom plate, a light source connected to the bottom plate, a sealing strip extending from the bottom plate, a plurality of cooling fins connected to the bottom plate and a rod sleeve connecting the bottom plate; the bottom plate is provided with a plurality of connection holes; the back plate includes a mounting portion, two extending portions extending from both sides of the mounting portion and two fixing portions extending from the extending portions; the mounting portion is provided with a rod receiving hole; the mounting portion is provided with a plurality of plate connection holes; the fixing portion of the back plate is provided with a plurality of fixing holes.