Often referred to as 'Jet Glue' this  similar glue is for hardening areas of your Pointe shoes to prolong their life. 
Make sure your shoes are clean and dry. After application leave
glue to dry for 24 hrs .

Take care not to touch the wet glue, as your skin will bond.

Apply the glue sparingly to the surface that you want to harden, such as in-between the shank layers, in the box, in the platform, and in some cases in
the arch area in middle of the outer sole.

Do not apply to outer sole areas that come into contact with the floor.

#jetglue