Felo 400 vs. 500?

[The Frisco Kid]

What's the difference between the two other than the grip color? I'm about the plunk down the money to get my set completed, and was curious if I'm missing anything not going with the 400's over the 500's that I already have (only 6 so far, though)

 

[Chadwilliam1]

The 400s are gel filled. I suggest the 410s with the hex bolsters.

http://german-hand-tools.com/Felo-screwdrivers.html