White background

Hello,

I'm saving as PNG.... but still, I cannot get rid of some grey background colour....

I think I have already set white as background colour, but it seems there might be something wrong...

Could you please check my SW model ??   The goal is to set in such a way that after rendering, I getcompletely white background colour, or completely transparent.  No gray at all !!

Can you help me??

thanks in advance.

SolidworksPhotoview 360