High speed steel drill bits, known as HSS drill bits are ideal for everyday drilling into metal and plastic but will last longer if reserved for metalwork. The HSS drill bit is generally reserved for metal work. The front edges cut the material , while the spirals remove the pieces left behind. This type of drill bit increases the hardness so they tend to be harder wearing than standard bits, enabling you to drill into a range of materials at greater speed. They are particularly good for drilling into metal as they are much more resistant to the heat that this generates.
This bit comes in 4mm