A system including a base mountable to a rail, the base including a receptacle for receiving an input/output (I/O) module, and an (I/O) module attachable to the base, the I/O module including communication circuitry disposed within a housing of the I/O module configured to communicate, via a terminal block, with one or more field devices configured to monitor and/or control an industrial automation process. The base and I/O module include mating male and female components, and the mating male and female components have a cross-sectional shape having a wedge portion and a radius portion, the wedge portion extending along a major portion of a midpoint axis bisecting the wedge portion and the radius portion.