Raspberry Pi fasteners

solving the fastening of a 3-level stacking: Raspberry Pi 3 model B+ in the middle, 7-inch screen below and StromPi v2 UPS above.

thread is M2,5. initially:


 * screen is attached to RPI with "spacer screws" (12 mm + male threaded end 3 mm)
 * UPS is attached to RPI with screw (12 mm) with tubular spacers (7 mm).

in this case, we are looking for:


 * long screws and tubular spacers: screw length 15 + 12 = 27 mm ideally, we take 30 mm (standard, threads on the screen can absorb an additional 3 mm)
 * or "spacer screws" (ideally 7 mm) with long (4 mm instead of 3 mm) male threaded ends