ITEM NAME:125pcs 304 Stainless Steel Hexagon Lock Nuts Nylon Insert Self Locking Nuts #gib Store Home Promotion Hot Item Add to Fav.Product material: 304 stainless steel. Product category: nylon insert lock nut. Widely used in the automotive industry (such as car hood locks), hardware, etc. 125 x Lock Nuts. M3 lock nut should be used with a M3 screw, by parity of reasoning.