The all-new Level Tank features the same revolutionary 37.5® technology as the brand's Level Tees to create the ultimate athletic wear. Active particles embedded in the fabric vent heat in warm conditions and trap heat when it's cold - technology that's proven to increase your body's efficiency by up to 26% at lactate threshold. Super soft fabric and flatlock stitching make it so comfortable that Runner's World chose it as the most comfortable running tank of 2020.