The EMIX WS-7xx series column speakers are aluminium made. With aluminium structure, it able to withstand harsh enviroment, making it suitable for both indoor and outdoor use. This series come in three model,WS-720, WS-730 and WS-740. WS-720 has one 4 inch loudspeaker and the number of loudspeaker increment by one for each subsequent model number increment. Each loudspeaker has maximum power of 20W making the largest model, WS-740 a whooping 40W.