UNDERDEEP item rarity tiers are four labels shown in square brackets on the item itself - [N] Normal, [R] Rare, [SR] Super Rare and [SSR] the top tier - and rarity is what unlocks your skills, which is the real reason to chase a higher tier.
The four rarity tiers
| Label | Tier | Unlocks |
|---|---|---|
| [N] | Normal | Skills N1 to N81 |
| [R] | Rare | Skills R1 to R174 |
| [SR] | Super Rare | Skills SR1 and upward |
| [SSR] | Top tier | The highest skill range |
The Normal and Rare ranges are easy to fill. Super Rare and SSR stay locked until the rare drops start arriving, which is why your skill slots can run out long before the best skills are available. The full unlock rules and what to do with each skill are in the skills and Orbs guide.
Underdeep item rarity tiers: the four labels and the suffixes
A drop can also carry an upgrade suffix - +1, +2 or +3 - which raises the item's stats. Real labels from a late-game character look like [SR] Halberd+1, [R] Chainmail+1, [R] Buckler, [N] Wand, [N] Gloves and [R] Magnifying Glass.
Eleven gear slots and eight loot slots
The character panel holds eleven gear slots:
Wpn1, Wpn2, Shd (shield), Helm, Armr, Glv (gloves), Leg, Acc1, Acc2, Itm1 and Itm2.
On top of that there are eight Loot slots for the items you carry out of a dungeon. The dungeon itself holds over 500 unique weapons, armour and accessories, but many of them are the same stat line under a different name, so a Rare item is usually what you actually want to wear. Filling the eleven slots consistently is a build decision, and the order to do it in is in the build guide.
Which tier you can realistically farm
Drops come from the tile band, so the tier you can realistically farm is set by the dungeon you have uncovered and by whether you can one-shot its best tiles. The band tables and the coordinates of the best tiles are in the drop rates guide.