I-unit yokubamba-yokubheka-yokubamba (eqinisweni "umshini wokubheka yokubamba") kuyinto isici esisha sokubheka okwenziwe ukuthatha izidingo eziningi zokubheka kwesitripi, okwenza kube nomthelela wemshini wokubheka okhokhelwe kanye nomshini wokubheka yokubamba. Izimo zakhe zezokusebenza kuyinto ukuthi isitripi isenza ukunyakaza okuphazamiseka phakathi kwezinye izinto ngezinye zokubamba kwesikhombisa kanye nokubheka okuphambene nokubamba okuphakathi okuphendulwa. Kuyakwazi ukuthuthukisa izifo zezigaba ezintathu zesitripi, njengokubamba kwesikhumba, isakhiwo somumo kanye nokubamba kwesokudla, futhi kwenza kube nokunikezela okuhle kwezikhumba.