Medical connectors need to be small, lightweight, and comfortable in use, but built for rugged handling and extended performance and reliability. Standard and custom interconnect designs and shapes have been applied to catheters, probes, and instruments. Applications have included neurologic testing system, laser surgery tools, bone healing stimulators, and blood temperature measuring catheters. Solid models for design planning are available on the web, while standard sizes and shapes are available off-the-shelf for sample review and prototyping.