Every wave in tiers 20-29 pays one column when it ends: the one for its kind.
What each wave pays
8| Item | Regular wave | Final wave | Big final wave |
|---|---|---|---|
 All-Purpose Strengthener | ×1 | ×1 | ×1 |
 Fine Sheet Metal | ×1 | ×1 | ×2 |
 Scrap Metal | ×1 | ×3 | ×6 |
 Cold Cuts | ×1 | ×1 | ×1 |
 Mystery Novel | ×1 | ×1 | ×1 |
 Tempered Glass | - | ×1 | ×1 |
 Broken Glass | - | ×3 | ×6 |
 Electronic Components | - | ×1 | ×2 |