Compare this Rocket Battle Droid figure
This Battle Droid was seen in an episode called "Rising Malevolence" during the first season of the animated Clone Wars TV Show. The droid has a removable jet-pack which plugs nicely and firm into the droid's back. The helmet with the lamp on top is glued in place on top of the Battle Droid's head and can not be removed. The lamp is not painted, simulating an "off-mode". Hasbro included a big "firing boarding claw" weapon, which is attractive to kids, but unfortunately the droid has problems holding the weapon and balancing problems take the fun out of it. The figure is made out of very thin and flimsy plastic, and it has problems standing on it's own as is, leave alone attaching a big, over-sized rocket launcher type weapon. If you decide to get this figure it'll give you some variety to your army of Battle Droids because this specific character has never been done before. But, considering that Star Wars figures cost about $8 - $9 these days, you might want to think twice about spending this much money on a below average Battle Droid.
Some battle droids are supplied with jet backpacks, which enable them to navigate for short distances through the vacuum of space to board Republic ships during battle.
Since they do not need oxygen, the droids are useful as part of raiding parties to infiltrate and capture ships.