Just make sure you get a wrench that will cover all or at least most of the torque range on a bike: Low-end 3nm - jockey wheel, 5nm - derailleur cable fixing, 10nm - hub cone locknut, 30 - cassette sprocket lockring, 40nm - freehub/crank arm. Then it should also be able to reverse torque (anti-clock) on bb and crank arms.