Excellent material Our self-locking nuts are made of high-quality stainless steel and nylon, which are corrosion resistant and can prevent loosening and twisting. Durable for long term use. Nylon Insert Threaded hex nut to prevent loosening, nylon insert prevents loosening and keeps the nut in place during vibration. These threaded inserts are waterproof, rust-proof and sturdy. Easy to Store Individual storage compartments are designed for easy storage. Thanks to the all-around transparent box, the assortment of self-locking nuts is clearly visible inside, even when stacked. Very strong and will not open during delivery. Wide range of applications Stainless steel nuts can be used to drive bolts, threaded rods and Allen screws. Ideal for folding beds, cabinets, motors, textile machines, workshops, etc. What you get You will receive 170 pieces / 7 sizes of the self-locking nuts the most commonly used, including M3:45; M4: 35; M5: 30; M6: 30; M8: 15; M10: 10; M12: 5. Product dimensions (L x W x H): 17.6*10*2.3cm;