Ribbed Black Short Sleeve Crop Top. Front is doubled layered. Back is single layer to keep you cooler. It has a slight compression with the 5% Spandex fiber content. 
 
Measurements (flat lay, not doubled)
X-Small  Pit to Pit:  13"   Length: 13 1/2"
Small      Pit to Pit:  14"   Length:  14"
Medium Pit to Pit:  15"   Length:  14 1/2"
Large      Pit to Pit:  16"   Length:   15"