This is a 20x key switch tester. The switch tester has one of each ZealPC switch. That is 4x Zilents, 4x Zealios, 1x Healios, and 1x Tealios lubed, and then the same non-lubed.
The purpose of this switch tester is to compare Zeal switches when lubed and when not. Great for those who have not had experience before with lubed swithces.
The lubed used was 3204 Tribosys, by Apex Keyboards and by /u/deftrocker.
Switch testers come in purple, gray, or black (see pictures).
Grab Keycaps for the switch tester here: