#4 Phosphor Bronze Internal Tooth Lock Washer

Manufactured from phosphor bronze, this #4 internal tooth lock washer provides dependable resistance to loosening caused by vibration and movement while offering excellent corrosion resistance. The internal teeth bite into the underside of the fastener head and the mating surface to create secure locking action with a low‑profile fit. Well suited for electrical, marine, and general‑purpose applications where conductivity, durability, and corrosion resistance are important.