An inflatable penile prosthesis represents a heterogeneous beam given that it is composed of a non-inflatable rear combined to an inflatable cylinder. In this model greater bending deflection was associated with more RTE length. Greater RTE length decreases the size of the inflatable device that can be implanted. The erect penis is subject to axial stress and bending deflection. Though further work is needed, these data support the notion that maximizing inflatable length by minimizing RTEs will improve overall erectile rigidity dynamics. Thirumavalavan N, Cordon BH, Gross MS, et al. Rear Tip Extenders and Penile Prosthesis Rigidity: A Laboratory Study of Coloplast Prostheses. J Sex Med 2018;15:1030-1033.