I designed this spring caps, because my heatbed screws are fixed with a M3 nut right at the heatbed. (because I got rid of the threads in he h-bracket) So I needed some caps, to take this into account.
For a complete set you have to print four of each cap. If you didn't fixed your heatbed srew with a m3 nut, just print eight of the one with the hole.
I printed this in PLA which works fine for me, but if you regulary use a hotter hotbed, you might want to print this in ABS or PETG