Puts it into the water, twisting it, then put it into the fridge for a few minutes and take it out. The cooling effect of the scarf will be more obvious. Don't hesitate indulge your furry friends with this cool ice collar. It's durable and will not deform after multiple cleaning. Features -Material: PVA. -Size(S): 31.00X8.50X0.10cm/12.18X3.34X0.04in; Neck Circumference: 19-31cm/7.48-12.18inch. -Size( ): 42.00X12.00X0.10cm/16.51X4.72X0.04in; Neck Circumference: 31-42cm/12.18-16.51inch. -Size (L): 63.00X18.00X0.10cm/24.76X7.07X0.04inch; Neck Circumference: 42-57cm/16.54-22.44inch. -Pets will feel very hot in the summer and other hot days, and they can rely on this cooling collar to dissipate heat. -The material is adopting the advanced cold technology, which mean it can resist heat and cooling. -If put in water, wring dry, and then put in for 10 minutes before taking out, cooling effect is more obvious. -Keeping dog or cat cool for a long time, allow your pet to play, rest or sleep comfortably. -It dose not contain chemicals, you can use it to cooling your pet with confidence. Package list: 1 x pet cooling collar