The Lyla Jr. with 37.5® technology is the perfect schooling style for even our youngest R.J. Riders. The patented thermoregulation technology has been proven to help your body manage its core temperature and, therefore, increase stamina. It keeps you comfortable by maintaining an optimum core temperature of 37.5° Celsius (99.5° Fahrenheit), which is ideal for peak athletic performance. The particles are naturally derived and work for the life of the product (they will never wash out!). Some colorways feature a unique patterned mesh, while others feature a tonal mesh.