Is there a reason Luke's saber on the sail barge appears to have a black control box?

[Gytheran]

Sorry if this has been discussed. I couldn't find information about it.

 

[v312]

I've always assumed that it is wrapped with some foam to make it little more comfortable to duel with.

 

[thd9791]

In many fight scenes in jedi the clamp or box is wrapped in gaff tape with/without cloth or foam. Looks like on the Sail Barge he only needed the box wrapped.