material: The round screw spacer is made of material, which has good temperature resistance, oil resistance, corrosion resistance and tear resistance, and long service life. 14 sizes: 40 pieces 3x7x3; 20 pieces 3x7x5; 20 pieces 3x7x6; 20 pieces 3x7x8; 20 pieces 3x7x10; 20 pieces 3x7x12; 20 pieces 3x7x15; 40 pieces 4x7x3; 20 pieces 4x7x5; 20 pieces 4x7x6; 20 pieces 4x7x8; 20 pieces 4x7x10; 20 pieces 4x7x12; 20 pieces 4x7x15. A total of 320 pieces, suitable for most screws. These spacers are , rust-resistant, stable and insulating. Simply measure the length needed for the screws and choose the appropriate spacer shorter than the screws 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, hardware accessories, etc., widely used to protect LEDs on circuit boards. Material: nylon colour: black Package Contents: 160 x M3 isolation columns(40 x 3 mm, 5/6/8/10/12/15mm each 20) 160 x isolation columns(40 x 3 mm, 5/6/8/10/12/15mm each 20) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.