What is the difference between the two portafilters my NEO Flex comes with?

The NEO Flex ships with both the Flow Control Portafilter and the Bottomless 2-in-1 Portafilter, allowing you to easily adapt and upgrade your Flair as you need. 

• Flow-Control Portafilter – Perfect for espresso beginners, the Flow-Control Portafilter features a restricted exit port, meaning the portafilter does the work of building the appropriate pressure needed for an espresso extraction. No dial-in required – just simple espresso brewing.
• Bottomless 2-in-1 Portafilter – Perfect for when espresso brewers are ready to control their extraction more. This portafilter requires a high-quality, espresso capable burr grinder, but means that home baristas can control the variables of each shot, and ensure their espresso if to their exacting standards.