Nordic Ice NOR1036 No-Sweat Reusable Long-Lasting Gel Pack, 8 oz. (Pack of 3)

Are these covered in a cloth fabric?

Is it possible to wash these? I wasn't sure if scrubbing them or popping them in the washing machine would damage the fabric.

Can these be used hot or cold?

Will these keep ice cream cupcakes frozen for about 45 minutes