These are narrower for 2004 so they get down the holes more easily and are made of stronger material (Polyester). Here you see Mark using the CNC machine to make the first one.
And here is the first v2 probe showing the new internal electronics. The hole on the left is for conductivity measurements so we can tell whet the exterior environment is like (especially if it is liquid water)
The new PCBs are very small and modular from left to right: Radio, analogue, digital.