I could only find the first edition online sans $$$, but ISO 9241-4 Keyboard Requirements said “The key displacement shall be between 1.5 mm and 6.0 mm. The pre

I could only find the first edition online sans $$$, but ISO 9241-4 Keyboard Requirements said “The key displacement shall be between 1.5 mm and 6.0 mm. The preferred key displacement should be between 2.0 mm and 6.0 mm.”