Well nuts = 24mm long x 8mm wide.
Countersunk Machine Screws M3 (3mm wide) X 30mm long.
Well Nuts have brass inserts & with stainless steel screws won't rust.
Description.
A problem-solving fixing suitable for use in virtually any construction material
from thin sheet metal to concrete.
Fixing expands to fit the internal profile even in irregular holes.
Use on boats -cars -caravans -campers -bike fairings- lighting- jet skis -picture hanging-brackets -electronics & many many other uses etc.
Resistant to vibration & corrosion.
Provides a waterproof seal.
Use 8mm drill for the hole.
UK seller
6001 positive feedback.
Buy with confidence.
Fast post.