Package Include--You will get 300pcs round spacers in 3 sizes, 100pcs/size. They will come together in a plastic box, making it easy for you to store the different sizes of round spacers. Size Detail--The length of the round spacer are respectively 3mm, 5mm, 7mm; OD 7mm, ID 3mm; The hole is about 3mm; Suitable for M3 M5 M7 screws. Premium Material--This set of gaskets is made of insulating plastic material, light weight and good insulation, which is not easy to deform and it is easy for you to carry and durable. Easy to Install--When you need to install it to car parts, just use the screwdriver tool to twist it tightly, no other operation is needed, simple and fast! Wide Application--The round spacer kit can be used for a wide range of projects such as microcontroller board fabrication, motion sensor mounting, controller board fabrication and flight controller stack fabrication.