As personal electronics "evolve" over time the "modular design" of the e-Holster case system enables its owner to almost endlessly modify the personal electronics they would prefer to wear. This evolutionary capability is achieved by a simple, yet functional design which enables connecting the e-Holster e-Harness™ Leather to any e-Pouch® case which are each designed to either be used alone or to be used like building blocks, one attaching to another. This unique "building block" modular design enables the owner to add a PDA when they are travelling, delete the PDA when they return from their trip, add a digital camera for a day at the race track, ad infinitum.