DC Power adapter?

In actuality, your device requires 10 volts DC.  And likely it's current requirements are LESS than 250 milliamps (¼ amp).  So any adapter that provides 10 vdc and at least .25 amp, will be usable.

Polarity is of course, of the utmost importance.

These adapters have copper wire and they have ampere rating. Therefore, if you have 10 Volt adapters with 30 Amp limit. Only they will be bulky. Cross sectional area of copper limits the current and voltage rating has no meaning here.

It doesn't matter what capacity adapter you use, the device will still only draw its 250mA. Anything over 500mA is just a waste of money

No problem.

As long as it can supply the correct voltage and is DC, and has the correct plug then you can use it. 

It won't "Force" those amps in there. The device will just take what it needs.

There’s a problem unfortunately, as you have voltage across low resistance, something called “voltage drop” occurs leading to less voltage and thus less current. It’s a tad difficult to explain as words, I’d recommend looking up voltage drop, and I wish you luck

ANY 10V MORE THAN 250mA CAN BE USED, LIKE BETWEEN 0.25A TILL 20A OR MORE IS FINE AND EVEN BETTER.

you'll be good .. 1000ma is 1amp btw ..but yeah, you could use like a 5 amp supply no problem, long as the voltage is right ..

You can always safely go with higher amperage than the device requires, just not voltage.  Devices only actually use as much amperage as they require.   

The downside is higher amperage power adapters are typically more expensive, would waste a little more electricity, and would be physically bigger. 

I hope so. It needs to be DC