Features:It is made of iron with enough strength. The screw is corrosion resistant and durable.Long screw size: length 30mm, fixed interface: 3.4mm. Short screw size: M5, 8mm length.Long screws are screws in special positions of the chassis, such as small screw holes in the fan position of the power bin or the front panel of the chassis, or screw holes for fixing the fan on the water-cooled cold exhaust. These screws do not contain nuts.Mainly used in PC, computer monitors, fans and other 3C equipment products.The short screw is a M5 flat head self tapping chassis fan general screw, which can be used in the general position of the chassis. Package Includes:30 Pieces Flat Head Self Tapping Screw/Set Specifications:Material:IronType:30mm Length Screw/M5 8mm Short ScrewColor:BlackLength of Long Screw:30mm/ 1.18inches; Fixed Interface: 3.4mm/0.13inchesLength of Short Screw:8mm/0.31inches note:Due to the light and screen setting difference, the item"s color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Our products are made with the splendid quality materials and are designed to provide you with the best possible user experience.