Rhodes Hammer Tips Sold Individual:
Red- 73 key: 1-23 88 key: 1-30
Green- 73 key: 24-33 88 key: 31-40
Yellow- 73 key: 34-46 88 key: 41-53
White- 73 key: 47-55 88 key: 54-62
Wood- 73 key: 56-73 88 key: 63-88
Order by color, these colors represent a certain section on your piano, counting from left to right on your piano. This will give you the number you are looking for.
Example: Red 1-23 Covers the hammer tips on a 73 note piano in the bass section from 1 to 23 counting from the bass up.