Printed on my RepRap Prusa i2 without support at 0.65mm extrusionwidth and 0.4mm layer height, single-perimeter, 20% infill.I use the clasp to charge loose li-ion cells in parallel. One couldalso wire the clasp for series connection of the cells, but Irecommend against that, as one needs to be much more careful whenassembling a pack, and accidentally short circuiting li-ion cells issomething to avoid at all costs.The banana jacks are experimental. My specimens are still going stongafter about 50 insertions using 0.6mm wire. The jacks appear to workbest with plugs that have a "cage spring". Classic plugs with a"banana spring" work too, but you need to orient them so that thespring opposes the wire for reliable contact. The "bunch of springywire" style plugs don't seem to work reliably because the contact wiresets itself between the spring wires instead of compressing any ofthem.As an alternative to banana jacks, the 4mm holes could be used asstrain relief for stranded wire soldered to the contact wires.