A Metal Keyboard is a keyboard

Keyboard (computing)

In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches...

 usually made of stainless steel

Stainless steel

In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....

, and mainly used in financial and security equipment, such as the ATM

Automated teller machine

An automated teller machine or automatic teller machine, also known as a Cashpoint , cash machine or sometimes a hole in the wall in British English, is a computerised telecommunications device that provides the clients of a financial institution with access to financial transactions in a public...

, and ODM

ODM

-Computing:* OpenDocument Master Document, an OpenOffice format* Object Data Manager, a DBMS for device configuration information in the AIX operating system* Oracle Data Mining, an optional extra for an Oracle database...

.Due to the tough, outdoor environment,it needs to be resistant to the dust, liquid, grease and other substances to avoid damage, especially to keep the electronic components inside in good working condition.
Metal keyboard parts include: metal function keypad, metal numerical pin pad, metal PC keyboard, with or without the trackball

Trackball

A trackball is a pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball about two axes—like an upside-down mouse with an exposed protruding ball. The user rolls the ball with the thumb, fingers, or the palm of the hand to move a cursor...

 or touch pad.