✔ Dual bug protection, 8 citronella rings included, clips onto your belt, fan and ultrasonic sound generator fairly quiet⚠ Back only goes on one way, no instructionsI've only been able to test how this portable insect repeller works in general so far. Springtime in Rhode Island was postponed thanks to 6-8 inches of snow over the first weekend in April. The unit itself is fairly small, about 1/4 the height of a can of soda, with a similar radius. It repels bugs in two ways: small citronella rings which mount in the middle of the top of the unit, and by producing an ultrasonic sound. Both options can be used individually or together, and are fairly quiet. The amount of citronella pushed out by the fan can be varied by twisting the top of the unit, The repeller runs on 2 AAA batteries (not included), which are installed by twisting the back of the unit. Eight citronella rings are included with your repeller.I ran into a couple of minor issues with this unit. First, there were no instructions included. It took a few minutes of fooling around with the thing to find out where the citronella rings went, and about as much time to figure out how to get the back of the unit back on after installing batteries. However, everything on this machine seems to be built fairly solidly (given the size), so I have high hopes when I finally get the chance to try it out in the wild...um...backyard.