Tempdrop brings the full fertility tracking solution to your smartphone whilst you sleep. Whether you are looking to increase your chances of conceiving, or are practicing fertility awareness methods, understanding you hormones or tracking menopause. Tempdrop is tailored to you. Before you go to sleep, press the drop-shaped button to turn on your Tempdrop sensor. Place the band on your upper arm and leave it on throughout the night. Remove once you are up for the day and sync with the Tempdrop app whenever convenient. Track your symptoms to verify ovulation and learn about your cycle phases. View the chart and interpret your results. Upgrade to premium for automatic interpretation. Sizing: S/M fits 8.5"-15.5"/21.5cm - 39cm L/XL fits 12.5"-18.5" /31.5cm- 47cm