Polycarbonate-TThe unique Directa Selecta mould guide makes even tiny crowns easy to handle, select and dispense. Simply select the right size and mould quickly and easily. A selection of sizes for each quadrant. Acclaimed coding system adopted by manufacturers the world over. Directa crowns are made of high quality polycarbonate which is resilient to mouth fluids and not brittle so it can be trimmed without risk of damage.