Adapter converter Help!!

Firstly, have you checked to see if the appliances are already dual voltage?

Secondly, if they're North American voltage only, don't bother buying a converter. The ones sturdy enough to handle the appliances will be bulky and heavy.

Your neighborhood large drug store will likely have travel appliances that are dual voltage. If not, try the travel section at Walmart. Buy one of each - the girls can share and it will cut down on suitcase weight.

Finally, if you have both 2 prong and 3 prong equipment, you will need separate adaptors.

Appliances that generate heat through electrical resistance, such as those you've mentioned, would draw significant amperage and would involve a pretty hefty (large, incredibly heavy) converter to change the voltage and frequency of the supply current to the needed current. In other words, I don't think you would want to bring one.

Even if the appliances your daughters want to bring are dual voltage (meaning they can work on U.S./Canada and European voltage and frequency) chances are there will not be an outlet in hotel bathrooms capable of supplying that amount of current.

As difficult as it may be for them, I would recommend you tell them no, they can't bring those devices. If it's a crisis of huge proportions for them, devices such as curling irons and hair straighteners can be bought in Europe in most large grocery stores or other general markets. You just may need to use them on an outlet outside a bathroom.

For dual current devices (such as mobile phones, tablet computers, electric razors, and similar, you should be able to find plug adapters from vendors such as Amazon.

RS FAQ Tip: https://www.ricksteves.com/travel-tips/phones-tech/electric-adapters-converters

Europe's electrical system is different from ours in two ways: the
voltage of the current and the shape of the plug.

American appliances run on 110 volts, while European appliances are
220 volts. Today's gadgets are "dual voltage," which means they work
on both American and European current. If you see a range of voltages
printed on the item or its plug (such as "110–220"), you're OK in
Europe. Some older appliances have a voltage switch marked 110 (US)
and 220 (Europe) — switch it to 220 as you pack.

Even older devices (and some handheld gaming systems) aren't equipped
to deal with the voltage difference — you'll need a separate, bulky
converter. (Consider replacing your appliance instead.)

I like the idea of buying the items when in Greece. I will double check here first but if not they can wait until we settle in and purchase one of each.