There are two known mold versions of this part:
61068 Slope Curved 2 x 4 x 2/3 No Studs [No Bottom Tubes]
This seems to be the original version, introduced in 2008. The inside is hollow without bottom tubes.
88930 Slope Curved 2 x 4 x 2/3 No Studs [Bottom Tubes]
This seems to be the modern version, introduced in 2010. The inside has three low bottom tubes.
The mold comparison image shows both versions.
Note that the modern 80930 exists in several minor mold variations, including mold 02 with horizontal reinforcement ridges and mold 04 with an additional cross support.
Click on a colored part below to see the Sets and MOCs that use part 88930 Slope Curved 2 x 4 x 2/3 No Studs [Bottom Tubes] 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.
There are 2 Mold variations of part 88930 - Slope Curved 2 x 4 x 2/3 No Studs [Bottom Tubes] in the database, in use between 2008 to 2020. See Molds and other related Parts.