The Castelli Core Mesh Short Sleeve Base Layer is an update of the 1980's fishnet style design. The older design used the holes to trap air between the skin and the second layer of clothing. By trapping air, it creates a boundary layer where air can remain warm and perspiration can move as vapor off the skin to the second, usually exterior, layer. The improvements Castelli brings are several. The mesh is made from a polyester hollow core fiber that is soft to the touch, wicks well and has great stretch. The shape is called bodywrap because it's designed to wrap or hug the body so the gaps are only in the mesh, not between the mesh and the body. The entire garment is mesh, save the hems and the "V" just below the collar.
The Castelli Core Mesh Short Sleeve base layer comes in White. There are three sizes -- Small/Medium, Large/X-Large, and XX-Large. Go for the smallest possible size you think will fit. It will stretch.