<prompt> Translate the following text to EnglishWachezaji wa barua za kawaida wanaelewa wazi kwamba vipande vya saturation vya 15 ounce vinaweza kusafirishwa kwa kibinafsi kwa kiwango cha chini cha kiwango cha A, wakati vipande vya 4 ounce haviwezi.  <response>: 23 Competitors understand clearly that 15-ounce pieces of saturation mail can be carried privately for less than Standard-A rates, while 4-ounce pieces cannot. 