hi,why CGRectMake(0,508,320,60)

hi, i have run your code in my xcode 6.4 , it's awesome , but why you set CGRectMake(0,508,320,60) , and it seems like can fullscrren in iphone5,can't fullscreen in others,and your code is set numbers in CGRectMake, it's so hard to read.