Thank you so much DanT.
That worked..! It would be great if you explain me the logic you put those parans () and double quotes ".
I was kind of struggling by putting them here and there, in the same line.
The drawback to doing that is that you're turning a numeric value into a string. This could make further processing of your output objects more difficult. Its generally better to set the unit size in the property name and leave the value as a straight numeric