What unit does the SizeOf return?

[Vu Luong]

import moa.core.SizeOf;
public static void main(String[] args) {

    float a = 10.0f;
    System.out.println(SizeOf.fullSizeOf(a));

    double b = 10.0D;
    System.out.println(SizeOf.fullSizeOf(b));

}

Output: 
16
24

I suppose the size of double and float is 8 bytes and 4 bytes respectively. What is the unit that the SizeOf uses?