What is an SSU and a SSSU

Discuss Median XL!
OwlWraith
Skeleton
3 | 0
Im fairly new at Median XL, ive gotten to Hell and made Tiered SUs, and ive learned to craft, but ive been seeing character builds with the words SSU and SSSU and I tried looking up what they are with no real luck, so im resorting to asking on the forum. I think I might have figured out the SSU is a Set Sacred Unique? But im lost as to what a SSSU is.
Siosilvar
Cow Ninja
1218 | 263
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there are no tiered SUs

TU = tiered unique, can be created from any tier 1-4 item (including amulets, rings, quivers, jewels)
SU = sacred unique with item level 105 (drop only in hell)
SSU = sacred unique with item level 120 (drop only in teganze+)
SSSU = sacred unique with item level 130 (drop only in fauztinville+)

the extra S's used to mean "secret" or "super secret" but now it just means more rarity