Reporting question for Fuse Holder Cap - Peavey

Fuse Holder Cap - Peavey

This looks exactly like what i need for my GK400RB head. Will this fit?

We do not have sizing information on your GK400RB to verify, but this item is 1 1/16" length with a ⅜" diameter, so if that is the size you need for your amp, these should fit.