For each 3 refine levels of Golden Wrench:
Increases damage of Power Swing by 7%.
Increases damage of Axe Boomerang by 5%.

For each 3 refine levels of Engine Pilebunker:
Increases damage of Boost Knuckle by 7%.
Increases damage of Arm Cannon by 5%.

For each 3 refine levels of Maxi Spanner:
Increases damage of Axe Tornado by 7%.
Decreases physical and magical damage taken from all size monsters by 5%.

[iRO Description]
Power Swing damage +7% and Axe Boomerang damage +5% for every 3 Golden Wrench upgrade levels

Knuckle Boost damage +7% and Arm Cannon damage +5% for every 3 Engine Pilebunker upgrade levels

Axe Tornado damage +7% and Physical/Magical damage -5% from enemies of all sizes for every 3 Maxi Spanner upgrade levels