Lululemon Women's Black and Gray Race back size 4 has a very good stretch.

Lululemon a lightweight version of our Luon fabric - Light Luon fabric is perfect for layering during sweaty workouts Light Luon fabric is sweat-wicking, four-way stretch and breathable wear with your bra of choice to get the perfect support racerback straps give you full freedom to move hip length helps this tank stay put and is great for layering imported Fit + function designed for: yoga, run, gym - everything! fabric(s): Light Luon fit: slim shelf bra: no support: low coverage: medium length: hip We like to mix it up and we love a tank that can handle it all. We left the shelf bra out of the equation to practice the power of choice and made the body out of Light Luon fabric with four-way stretch to move with us through our workouts. The long length means we can focus on our back bends and burpees without tugging at our clothes.