High-quality material: The round screw sp is made of high-quality nylon material, offering good temperature resistance, oil resistance, corrosion resistance, and tear resistance, ensuring a long service life. 14 sizes included: 40 pcs 3x7x3; 20 pcs 3x7x5; 20 pcs 3x7x6; 20 pcs 3x7x8; 20 pcs 3x7x10; 20 pcs 3x7x12; 20 pcs 3x7x15; 40 pcs 4x7x3; 20 pcs 4x7x5; 20 pcs 4x7x6; 20 pcs 4x7x8; 20 pcs 4x7x10; 20 pcs 4x7x12; 20 pcs 4x7x15. Total of 320 pieces, suitable for most screws. These sps are rust-resistant, stable, and insulating. Simply measure the required length for the screws and select the appropriate sp that is shorter than the screw to allow the board to sit flush with the wall. Wide range of applications: Suitable for micro-motors, automobile manufacturing parts, electronic products, instruments, machinery, stationery, automation equipment, toys, and hardware accessories. Commonly used to protect LEDs on circuit boards. Material: Nylon Color: Black Package Contents: 160 x M3 isolation columns (40 x 3mm, 20 each of 5/6/8/10/12/15mm) 160 x M4 isolation columns (40 x 3mm, 20 each of 5/6/8/10/12/15mm) Only the above package content is included; other products are not included. Note: Light reflection and differences in display screens may cause slight variations in the color of the item shown in the picture compared to the actual product. Measurement may vary by +/- 1-3 cm.