Made from strong heat treated, hardened steel.  Comes in black version or silver colored versions.  Silver colored versions are nickel plated, and are made from heat treated, hardened steel.  Thus, the silver version is of the 4.5mm security bit is much stronger than the black version. The bit measures 5 cm (about 2 inches) in length.  Bit will fit any standard 1/4" screwdriver handle.The 4.5mm security bit allows you to open Sega Genesis, Sega Master System, and Sega 32X games.The 4.5mm security bit allows you to open Super Nintendo, Nintendo 64, Game Cube, Virtual Boy, Game Gear, TurboGrafx 16, and TurboDuo systems (video game consoles).  Opening those games and systems will allow you a greater ability to clean and restore functionality.  Additionally, it'll allow you, when necessary, to access a game or system's battery in order to restore save game functionality.