They're used to instantly whip cream with pressurized gas. You insert a cannister containing nitrogen here ...

[ She leans in, reaching past Tifa to point at the receiver. ]

Fill the reservoir with heavy cream, press that button, and it'll dispense whipped cream from this spout.

[ There's a fair few gadgets here that Mitsuru doesn't recognize - her culinary experience is decidedly limited - but she's whipping siphons of various designs in a number of high-end coffee shops.

[ ... just as she's seen tea diffusers like the ones sitting on a shelf by Tifa's shoulder.

[ She wonders how much those cost ... ]