My son's comp singlet is made by Under Armour and he has managed to outgrow his Adult XL. (he is both tall and stocky.) I am having a heck of a time finding a reliable Under Armour fit guide online nor can I find out if they even make a larger size. Also it appears UA and GK are in a partnership or merged? Hard to tell and that is confusing me too. As usual my online searching turns up info relevent to girls rather than boys. Any suggestions/info appreciated. Thanks!