This USB mini vacuum cleaner isn't really a vacuum cleaner per se. Inside of it there is a fan that with a net over it, which prevents the junk going inside the propeller.
The suction is almost non-existent, and as such this vacuum cleaner is suitable for cleaning bread crumbs out of your keyboard, or collecting ash that you accidentally dropped around your laptop during one of those nights (which really aren't that different from all others).
USB Mini Vacuum Cleaner – REVIEW
There are two caps that this device comes with: the rubber oval piece of tube with a large hole, and a cap with 3 smaller holes and a brush with thin synthetic bristles.
This is not the most useful device out there, but a price tag of about $2 with free shipping make it an easy impulse purchase that won't leave you feeling dirty for being an Aliholic.
Product link: http://ali.ski/_dhC- (AliExpress)
Product link: http://goo.gl/CbQdPo (BangGood)