Symmetric Inside Ridges: compare to 11153.
Click on a colored part below to see the Sets and MOCs that use part 13731 Slope Curved 10 x 1 [Symmetric Inside Ridges] in that color. You can find an overview of all LEGO Colors here.
If a color is missing, it probably needs to be added to a Set Inventory.
This part has been used by MOCs in the following colors but not officially released.