HIGH QUALITY: All products are made of strong nylon material which is corrosion resistant and durable. With washers to increase contact area, reduce pressure and protect parts and screws. Ideal for electrical connection with household and commercial appliances, automotive and marine applications. Pre-sorting identifies and avoids losses quickly. Very convenient to use. Easy to install and durable, 8 popular sizes including the most common and popular sizes-M2, M2.5, M3, M4, M5, M6, M8, M10, various sizes to meet all your needs M2 (5 * 2 * 1) mm outer diameter * inner diameter * thickness M2.5 (5 * 2.5 * 1) mm outer diameter * inner diameter * thickness M3 (6 * 3 * 1) mm outer diameter * inner diameter * thickness M4 (8 * 4 * 1) mm outer diameter * inner diameter * thickness M5 (10 * 5 * 1) mm outer diameter * inner diameter * thickness M6 (12 * 6 * 1.2) mm outer diameter * inner diameter * thickness M8 (16 * 8 * 1.5) mm outer diameter * inner diameter * thickness M10 (20 * 10 * 2) mm outer diameter * inner diameter * thickness