NEW BRITISH 1/4 ZIP COOLMAX SHIRT
Comfort! CoolMax® has proven benefits that keep you cool and dry in any setting. From high-intensity performance workouts to everyday casual wear. Now stay cool and comfortable in any situation. Recommended as a base layer undergarment when wearing body armor. Lets your body breathe. 1/4-zip neck. Short sleeved.
These were issued to the British soldiers for their deployment in hot environments. Football players and race car drivers wear these to stay cool also. Usually very expensive but right here very affordable :-)