The Under Armour Women's ColdGear Authentic Leggings are a popular choice for women's tennis base layer bottoms in colder climates. These leggings are made with Under Armour's ColdGear fabric, which traps heat and keeps you warm without weighing you down. They have a compression fit that supports your muscles and reduces fatigue. The leggings also feature a wide waistband and a hidden pocket for convenience. Whether you're playing in chilly temperatures or need extra warmth during winter training sessions, these leggings are a reliable choice.