Yeah it certainly does blow, hence the name rocket blower haha.

The Giotto ones though are quite good in that you get a good blash of air that will blow dust off your lenses without you having to touch the glass with a cloth, this prevents small scratches forming where dust is dragged across the glass by a cloth. They work most of the time but sometimes you will still need to use a brush or cloth. You can also use the blower to get dusk bunnies off the mirror, sensor and pentamirror/pentaprism.

Hope that helps, as far as these types of blowrs go, this one is pretty much the ducks nuts. Try and resist the urge to throw it like a american football (they fly pretty well).