HERO5 thru HERO7 have one style. HERO9/10 & 11 are larger and squarer. You can't use the newer filters on HERO5.

For HERO5 (ND Fiters): https://www.polarpro.com/products/hero7-hero6-hero5-black-shutter-collection

or just replacement clear: https://www.amazon.com/Replacement-Protective-Camera-Protector-Accessories/dp/B08DKVX4VP