ʻO ka pahu pahu kahi pahu maʻamau i hoʻohana ʻia no ka lawe ʻana i nā ukana, i māhele ʻia i loko o ka pahu maʻamau honua a me ka pahu maʻamau.
I mea e maʻalahi ai ka helu ʻana i ka helu o nā ipu, hiki iā ʻoe ke lawe i ka pahu 20ft ma ke ʻano he pahu maʻamau hoʻololi (i kapa ʻia ʻo TEU, Twenty-foot Equivalent Units).