Round Cable Plastic Backshell This range of 103 Series Mini Delta Ribbon (MDR) Backshells are .050" Plastic Shielded Junction Shells for Round Cable. The design of these 103 Series MDR Backshells consists of a plastic cover with straight cable exit and a two piece metal junction shell. Part numbers 103xx-3210-00x for the 103 Series MDR Backshell have quick release latching and a one piece plastic shell. Part numbers 103xx-3280-00x for the 103 Series MDR Backshell have quick release latching and a two piece plastic shell. Part numbers 103xx-32J0-00x for the 103 Series MDR Backshell have thumb screws and a one piece plastic shell.