“WTF Permanent Sticker” series. Set of 50 stickers with black mini marker. Size: 10 x 6 cm.

Two factors make the WTF stickers particularly durable:

- The material from which they are made is crumbled into pieces when rubbed off, making it impossible to peel them off in one piece.

- The adhesion of the sticker becomes stronger and stronger over time until it practically melts into the surface.