A pluggable module includes a pluggable body extending lengthwise between a mating end and a cable end. The pluggable body has a first end and an opposite second end with sides extending therebetween along a length of the pluggable body. The first end, second end and sides define a cavity. An internal circuit board is held in the cavity. The internal circuit board is provided at an end of a cable communicatively coupled to the internal circuit board. The pluggable body is configured to be plugged into a receptacle assembly such that the internal circuit board is communicatively coupled to a communication connector of the receptacle assembly. The pluggable body is defined by a first shell including the first end and the sides and may be formed by extrusion and may have increased thermal conductivity and a second shell including the second end.