The performance requirements specified herein cover a backshell intended for use with a MIL-PRF-64266 or MIL-DTL-38999 connector plug or receptacle in a fiber optic only application. This backshell is intended for the cable harness configuration in which a bundle of single fiber cables (simplex optical cables) are routed through convoluted tubing to the connector plug or receptacle. This backshell is used for interface with the connector plug or receptacle on one end and with the convoluted tubing on the other end. Environmental resistant features include ability to restrict movement, position, and twist of each cable in addition to eliminate or reduce penetration of various environments. This backshell is one of a solid shell configuration. This configuration consists of a solid shell (or body) with coupling nuts on both the ends, gland components and convoluted tubing interface components. One coupling nut on the shell mates with the connector, the other both houses the gland and mates with a convoluted tubing interface.