Features:
Lock Nuts ensure a secure hold; reduce slippage
Plain Steel fasteners are suitable where strength and value are the primary considerations
Drive system is a hexagon-shaped head
Coarse threads are better for brittle materials, and will assemble and disassemble more quickly than fine threads
Ensure a lasting hold for any project
Self-Locking, Nylon Insert 
Carbon Steel Lock Nut Zinc Plated Finish, Left Hand Threads, Self-Locking/Nylon Insert M5 0.8 Threads 

Specifications: 
Quantity: 10 pcs
Material: carbon steel (iron)
Color: whites
Threads: 0.8
Inside diameter: 5mm(M5)/0.2 inch
Height: 7mm/0.3 inch
Package size: 95 x 80mm/3.7 x 3.1 inch
Net weight: 20.5g
Package weight: 21g