It has a small hole on the back and i don't know exact size but you can see the measurements. The Lululemon Water Bound Singlet Tank Top in purple, size 6/8, is a solid colored activewear top perfect for various occasions. With a chest size of 17 inches, this pullover tank offers a regular fit and is part of the Water Bound Singlet product line. It features UV protection, is lightweight, stretchy, quick-drying, moisture-wicking, and wrinkle-resistant. Ideal for activities such as gym training, beach outings, water sports, and running, this tank from the reputable brand Lululemon is a versatile and comfortable addition to any woman's activewear collection.