If you want to play the Catan base game with 5 or 6 players, just add this base game extension which contains green and brown playing pieces, hexes and more.
contains
11 Hexagonal Regional Tiles
2 Frame Pieces with Harbors
2 All-Sea Frame Pieces
10 Wooden Settlements
8 Wooden Cities
30 Wooden Roads
25 Resource Cards
9 Development Cards
28 Number Tokens
1 Rulebook