This great little tool combines everything you love about the traditional hera marker, with a point turner at the other end!
 
Use the curved side for marking lines in your fabric wherever you don't want to use a pencil or anything that might leave a residue.  Simply press firmly and drag the fine edge of the hera marker wherever you need to make a mark or guideline on your project.  They are also handy for pressing sharp creases.
 
And use the pointy side for pressing out corners corners with lovely sharp points. So handy!