(Craft) Mastery
From Flexible Survival
"Your group specializes in the creation and modification of (Craft) items. You have to use more parts, true, but you can make things others can't dream of. You use +25/50/100/150% the normal amount of salvage, but the required craft skill is reduced by 10/20/30/40%."
Each salvage type must have its Mastery purchased separately. When you attempt to create an item with a skill requirement higher than your base skill, you will be prompted for what level of perk you wish to use. If you specify a higher level than is required to make the item, it will still consume the extra salvage from the specified level, so be careful!
Levels to improve: 2
Freecred to improve: 10k/20k/30k/40k