There are three known mold versions of this part:
3622 Brick 1 x 3 Solid Bottom Tubes without Cross Supports
This seems to be the original version, introduced in 1978. The inside has two solid bottom tube, but without cross supports connecting the bottom tubes to the side walls.
3622 Brick 1 x 3 Solid Bottom Tubes with Cross Supports
This seems to be a later version. The two solid bottom tubes are connected with the side walls by cross supports.
3622 Brick 1 x 3 Hollow Bottom Tubes with Cross Supports
This seems to be modern version. The two bottom tube are hollow, and connected with the side walls by cross supports.
Courtesy of Rebrickable
The mold comparison image shows all three versions. As long as we are unsure when the mold change happened, we cannot create different parts for these molds. A transparent version with 'Frosted' Horizontal Line (3622f1) has, as yet, not been found in any set.
LEGO mapping includes Design ID 45505 for transparent (PC) parts.
Basic Brick Quicklinks:
Click on a colored part below to see the Sets and MOCs that use part 3622 Brick 1 x 3 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.