You select your 'Base Currency', enter your value into the textbox and the results appear below. The results consist of every currency in the world, virtually. You have to scroll down to the one you want to see.

It works, but the design is highly impractical, to say the least.

When you click away, it forgets everything you just did: your base currency, your value, everything. It switches back to USD and '1'. So, every time you go to use the add-on, you have to reset your settings.

Again, highly impractical. Poorly thought out.

The add-on also takes about two or three seconds to load any time you click on it. I can't imagine why it should be so slow.

Very awkward to use. Cannot recommend it.

I couldn't select the currencies I was interesting in, it just showed a long list of currencies that I had to scroll through.

Looks nice and simple, however missing any fine tuning and almost first currency I need XPF is not there.