A naturalodor neutralizer with scent of apple. Ona Block Series is for small spaces. There is no need to assemble ONA. The only thing you have to do is remove the cover and place it in the desired spot. ONA Block has a small size container that fits anywhere. It has the same formula that has made ONA so famous. Very convenient for smokers and hydroponics growers. Block life cycle is 5 to 6 weeks, depending on the air flow, temerature and humidity level. Measures 3" x 3"