A spraying device includes a housing that has a spraying unit and a trigger assembly. The spraying unit is a removable insert within the housing. The spraying unit includes an air chamber that is coupled to a liquid tank. A front end portion of the air chamber has a nozzle. The air chamber receives a liquid tube that opens in the nozzle. The liquid tube receives a needle and the needle and the liquid tube are coaxial with each other. The trigger assembly controls the flow of liquid through the liquid tube by positioning a tapered front end of the needle. The trigger assembly includes a trigger that has a first position and a second position. In the first position, the opening of the liquid tube is closed by the needle. In a second position, the liquid tube is opened to discharge a liquid from an opening of the liquid tube.