Strong boxes are wood-based containers weighing 10 units with no item weight reduction. Previously they weighed 100 and had considerably more inventory slots per tier than Backpacks, but this was changed with the release of Live Update 54 to be equal.
The most common use for a strong box is for the bank or house vault, and, at early levels, storage containers for the broker.

Strong boxes have new boxes at each tier, with new recipes appearing on recipe sheets ending in "5" (e.g., 25, 35, 45, etc) for each crafting tier. They come in both common and mastercrafted versions, with the mastercrafted version in each tier having 4 slots more than the common version (effectively giving you the size of the next tier).

Sizes by tier Edit

Tier	Slots	Wood Type	Name
1	8	Severed elm	Pristine elm strong box
1	12	Severed alder	Pristine alder strong box
2	12	severed maple	Pristine maple strong box
2	16	Severed Bone	Pristine bone strong box
3	16	severed ash	Pristine ash strong box
3	20	Severed Fir	Pristine fir strong box
4	20	severed briarwood	Pristine briarwood strong box
4	24	Severed Oak	Pristine oak strong box
5	24	severed teak	Pristine teak strong box
5	28	Severed Cedar	Pristine cedar strong box
6	28	severed sandalwood	Pristine sandalwood strong box
6	32	Severed Ironwood	Pristine ironwood strong box
7	32	rough lumbered rosewood	Pristine rosewood strong box
7	36	rough lumbered ebony	Pristine ebony strong box
8	36	redwood lumber	redwood strong box
8	40	mahogany lumber	mahogany strong box
9	40	sumac lumber	sumac strong box
9	44	eucalyptus lumber	eucalyptus strong box