The Under Armour Women's HeatGear Armour Long Sleeve is a top-rated base layer top for women's tennis on Amazon. It is made with Under Armour's HeatGear fabric, which is lightweight and provides excellent breathability. The long sleeves offer extra coverage and protection from the sun's harmful rays. The top features a compression fit that supports your muscles and reduces fatigue during long matches. With its top ratings and positive reviews, this base layer top is a popular choice among women tennis players who prioritize comfort and performance.