Plated-through (PTH) slits / elongated holes, or better plated-through milling, is producible from 0.8mm width. Smaller diameters are enlarged to 0.8 mm in diameter.
If the through-plating is realised within the circuit board it is called plated-through slits, through-plating on the outer edge of the board is called sideplating.
Basically, each milling with copper connections on TOP and BOTTOM will be produced as plated-through hole (PTH). Is a non-plated-through (NPTH) milling desired, the milling should be exempted from the copper (min. 150μm).
Are plated through slots / millings desired, it is advisable to select these in the online calculator.