These spacebars come in OEM profile and are 6.25u in length (standard spacebar size). They are MX and MX compatible stems. The keycap itself is made from ABS material and then undergoes an electroplating process with copper -or- silver alloy for long-lasting wear/tear resistance. Fading and corrosion will not be factors with these awesome spacebars! These are plated with just the right amount of material to be useful but not intrusive...the perfect weight!