If you are building computers then these are an absolute must PC Computer Screws & Standoffs Kit 228pcs: Set contains: 24 pcs Main board conventional copper column (M3 x 6 + 6),30 pcs Main board fixed screws (M3 x 5),30 pcs CD-ROM set screws (M3 x 4) 30 pcs CD-ROM set screws (M3 x 4),30 pcs Hard drive screw (M3.5 x 5) ,6 pcs Chassis hand twist screw (black M3.5 x 5) , 24 pcs Chassis high-strength screw (M3.5 x 6) 24 pcs Conventional chassis fan retaining screw (white zinc M5 x 10) , 24 pcs Conventional chassis fans retaining screw (black M5 x 10) Material: metal+ plastic Color: photo colour Box size: 13.2cm/5.20 inch x 7cm/2.76 inch x 2.3cm/0.91 inch (L X W X H) Weight(packaging weight excluded): 8.00oz Note: The above numbers behide M are for screw tooth diameter x length,the unit is mm. Example: copper column (M3 x 6 + 6) It's specifications for: screw tooth diameter is 0.11inch,teeth length is 0.23 inch,hexagonal copper column upper part is 0.23 inch long (Attention: The main board copper column for the conventional chassis use teeth for 0.11in in diameter,there may be a few special specifications chassis can't compatible with use.) Package Includes: 1x set of computer screws (228pcs) Only the above package content, other products are not included. Note: Light shooting 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.