Depending on the temperature of the room your baby sleeps in, you can adjust the tog of their grobag to keep them comfortable. The higher the tog, the warmer the baby sleep bag , Grobags come in 0.5 tog, 1 tog and 2.5 tog options. All Grobags come with a free nursery thermometer, or for greater peace of mind a Gro-egg gives you a digital reading as well as glowing indicator of the temperature.