The Portage Dropout is designed to make your frame more durable, and to make your frame more usable in the long term. By keeping the frame interface to 2 simple holes, and putting all interfaces and threaded parts on the replaceable aluminum inserts, the Portage Dropout allows for adaptations to future new standards, multiple different axle spacings, different brake mount standards, different derailleur mounting standards, adjustable chainstay lengths, single speed capabilities, and more. Anything you bugger up is easily replaceable in just a few minutes. And with its wide bolt spacing, and investment-cast frame weldements, it makes for a stronger frame than other adjustable dropout systems on the market.
See an exploded diagram HERE.