Pilot FriXion Erasable Rollerball Pens - Blue - Pack of 3

is the eraser part of the pen or do you buy it seperately

I do a lot of patchwork; could I use these pens on fabric and iron off the ink afterwards?

If you wrote some notes on a pad of paper and accidentally left the pad in the sun on a hot day, would it erase the writing?

can it be used on newspapers crosswords