Toyota 2006 Tundra Owner's Manual page 355

Type C
344
'06 TUNDRA_U (L/O 0508)
Type C cup holders are equipped with
a detachable adapter for each holder.
When you remove the adapter, a bigger
cup can be held in the holder.
Type D
Type E
2006 TUNDRA from Oct. '06 Prod. (OM34458U)