In response to concerns over proliferation of new and different technologies in leads and lead connectors, a voluntary standard for 3.2 mm unipolar and bipolar pacemaker leads and connectors has been established. One major difficulty overcome in the process was the design of the voluntary standard. The greatest controversy centers around the design for the sealing mechanism for the connection of the pacemaker to the leads. Some suggest that the sealing mechanism should be in the form of seal rings on the lead; others believe that it is preferable to have the seal rings inside the pacemaker cavity. The new voluntary standard finally agreed upon represents a compromise position. It is a standard that appeals to future development since it favors leads smaller than those in current distribution, and provides for backward compatibility with existing leads. In addition, it allows each manufacturer as much design flexibility as possible. It is hoped that this voluntary standard will be universally accepted throughout the industry.