This is the smallest of the Giottos "rocket" blowers. Operation is simple, just squeeze the bulb to generate a blast of air to blow dust off your camera lens. The "rocket fins" let you stand it up so the nozzle has no chance of picking up dirt or mud that might block the hole or transfer to your lens. They also have holes in that you could use to attach the blower to a neck, camera or bag strap.
It is obviously less effective than its bigger brothers, it holds less air and there's less to grip to aim and hold it steady. You need to pump it a little harder, and it requires some practice to keep the nozzle pointing in the right direction as you squeeze it. I find it best to close my hand around it, almost making a fist, with the nozzle sticking out at a right angle to my fingers.
If size is no issue, better to buy the bigger versions. But if you are short of space in your camera bag, or you want something unintrusive that you can hang on a neck or camera strap - then this is ideal. Once I got the hang of using it, I've found it very effective for keeping my lenses etc dust-free out in the field.
It's amazing...not small, nor big, just the right proportions to assure a functional and powerful air blow. Furthermore the materials (silicone) seems to be really durable and reliable. Definitely a good purchase.