General information: SPDT / GX Modes

Off:
When you click, the leaf spring goes down, and the shrapnel (blue) makes contact with the bottom contact point (green). Contact is made, and a click gets registered. This is the classical way most mouse switches work.

GX Speed Mode: In the 'resting' position, the shrapnel (blue) (part of the leaf spring) maintains continuous contact with the top-bottom contact (pink). When the leaf spring, and thus the shrapnel (blue), moves downwards, the loss of contact with the top contact (pink) is registered. This loss of contact is processed as a click. Since you do not have to wait for the leaf spring and shrapnel (blue) to reach the bottom contact, this method is faster.

GX Safe Mode: This mode acts as a double confirmation, meaning that before a signal is registered, the top contact (pink) must be released while the bottom contact (green) must be connected. This serves as a hardware-based double-click prevention. Speed-wise, this method is (almost) on par with the Normal / Off mode but offers many advantages when a switch starts to age.