Silicone neck cooler, providing a comfortable cooling effect. Blue - Men's (L) White - Women's (M) Used in the summer, only about 2-3 times. There is some color transfer from storing the blue ring on top of the white ring, but there is no problem with use. It feels cool and pleasant on the neck. ◎ Reusable ◎ Stretch with both hands and put around your neck ◎ Put in the freezer to cool ◎ Instant purchase OK