Questions about Noqon NSP312 300W/12V

The supplier Swissbat24 offers exactly this device with a Swiss socket. This is absolutely essential for me, as several of the devices I want to plug in have a 3-pin CH plug, which unfortunately does not fit into the Schuko socket. Can I possibly buy the CH version from Digitec? Is there an oscillator measurement for "pure" sine wave voltage? I really need a perfect sine wave voltage, as I want to use it to power a high-end sound system (draws max. 80W), among other things.

peak wattage, how high and for how many seconds?