Sonic Booster

Doesn't seem to be, probably the same as the Goblin Rocket Launcher, you can have two equipped of that one.

Engineering in WotLK will be so much more fun, and handy than BC, in addition to extracting motes and making bombs, imagine this:

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• Being able to shoot a rocket from your gloves once a minute with Hand-Mounted Pyro Rocket
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• A parachute every minute, embroided into your cloak: Flexweave Underlay
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• 150 % sprint every 5 minutes with Nitro Boosts on your boots.
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• Carrying around a multi-tool that ALSO serves as jumper cables: Gnomish Army Knife
• 
  

Also it's nice to be able to make trinkets such as the Noise Machine and the Sonic Booster

And there might still be more =)

*EDIT*
150 % sprint nao ?

Now requires 420 Engineering

materials needed

34 cobalt bars*
4 crystallized earth
2 crystallized water

* averaging 2 bolts per cobalt bolt combine