The 18 mm width clips onto a DIN rail, occupying one module position in a distribution board.
This part is marked obsolete by the manufacturer. If you are freezing a new design, check the current Domae or Acti 9 catalogue for an active C-curve 25 A 1P MCB with the same 6 kA rating; the form factor and DIN-rail footprint are standard across the family, but verify the tunnel terminal range and any accessory compatibility before substituting.
If your installation requires a higher SCCR (e.g., 10 kA or 15 kA), this part is not the right choice — look to the Acti 9 range for higher interrupting ratings in the same footprint.
Strip length is 14 mm for solid/stranded AC wiring. The IP20 finger-safe front is standard for enclosed distribution boards; no special sealing is required inside a panel. The 18 mm width per pole means a 1P breaker occupies a single 18 mm module — plan your busbar and comb-bridge layout accordingly (confirms comb-busbar compatibility).