From Brotato Wiki
Robot Arm
Item
Tier 4
Stats
+6 Armor
+6 Engineering
-2 HP Regeneration
-2% Life Steal
+6 Engineering
-2 HP Regeneration
-2% Life Steal
Price
90
Unlocked by
Win a run with 
Engineer
EngineerItem
Robot Arm is an in-game item that can be bought from a Shop or can be found in a Crate. Most Items modify the Stats of the player, and some of them provide additional effects.