Flow's 19 Hole Baseplate: The baseplates of these bindings have 19 holes (yes 19!) positioned in such a way that you should be able to mount these bindings on any snowboards that have a hole pattern. [(the only exception to this that we know of are the new Burton EST bases) if you have one of those snowboards, though, you knew that already]
Flow Powerstrap: Flow bindings got famous for having one big instep strap, as opposed to the standard ankle strap/toe strap combo. Having one, bigger, wider strap allows the rider to cinch it down as tight as possible without fear of cutting off his circulation. Also the Powerstrap is convenient because you can set the position of it once and then enter/exit the boot through the unlockable backplate.
2 Mini-Ratchet Buckles, 2 Quickset Buckles: As opposed to the other Flow bindings with 4 Quickset buckles that you set once at the beginning of the day (and don't really touch after that), these bindings have a mini-ratchet buckle at the lower and upper end of the Powerstrap. This means you can dial in a different fit from run to run, tightening and loosening with the power of a well designed ratchet.
DuPont POM plastic: The hiback and baseplate are made with a super durable DuPont plastic that will not be brittle in very cold temperatures, and provide a very stable binding for high-speed riders.
Quick Adjust Straps: No tools are needed to make basic adjustments to the strap(s) of this binding. Even though most resorts have a bunch of tools next to the lifts, its nice having the ability to fix or tighten them mid run.
Adjustable Forward Lean: Adjust the position of the highback for more flexibility for freestyle, or more forward to get better performance at high speed.
Ventilated Hiback: Air holes (speed holes) in the back plate help keep the airflow (hopefully your pants are breathable!) around your calf from being completely stagnant (and therefore sweaty).
Flow Stickers Included: A page of stickers comes in each binding box for maximum
vandalization customization. Just for fun. And also the instructional guide opens up and turns into a poster. Also just for fun.