These occupy the middle ground between the cordless items and the monstrous professional compressed air stuff... this isn't about brute force though and mine has worked out fine for me.

• Screwing and Unscrewing.

• RPM is the key for vibrating seized items.

• Variable torque and speed are handy.

• Always wear eye-protection

• Always use shock-protection

• Always wear hearing-protection

• Consider impact-protection