The size of "M" t-shirts in centimeters from shoulder to shoulder = 46 cm 
and the width of the t-shirt from armpit to armpit in centimeters = 51 cm

The size of "L" t-shirts in centimeters from shoulder to shoulder = 50 cm 
and the width of the t-shirt from armpit to armpit in centimeters = 55 cm

The size of "XL" t-shirts in centimeters from shoulder to shoulder = 54 cm 
and the width of the t-shirt from armpit to armpit in centimeters = 58 cm