Box of Gears is an item that is perfect in every way. It follows the design prenciples of SOTS. It is pay to win in a sense. In the meaning that the more hardware you buy the more benefit you shall receive.
Each stack of the box will increase your move speed, attack speed, damage, jump count, regen, and armor by an amount that scales with your fps(FPS/30).
If you change your fps cap while in posession of item weird stuff will happen and you'll have to start a new run. Following proudly in the footsteps of the SOTS patch.