In Lords Mobile Siege Toughness research increases your siege engine defense. It is found in the military tree.
There are 10 levels in total and once maxed it will have increased your Siege Toughness by 135%. You need to have research Siege Attack before you can unlock this ability.
The table below has the resource cost and time to upgrade each level. It also shows the might and rewards granted. You can find out your times based on your own research boost by using our research calculator.
Siege Toughness Research Requirements
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