What is the difference between RX and RX Pro?

The RX Pro models (5-finger, 3-finger and Mitten) have several changes and upgrades:

1) In the RX Pro we added a hook and loop fastener loop around the liner, which attaches to the shell, giving the RX Pro all the benefits of both a removable and a fixed liner glove. Less material at the cinch cord also makes it easier to go over the cuffs / sleeves of your jacket. 

2) The RX Pro has a wider cuff opening, which makes them easier to fit over the cuff / sleeve of your jacket.

3) The RX Pro has softshell on the back of the thumb to wipe your nose. It is a more stretchy material than the previously used microfiber material, so it fits better and provides better dexterity. And it's more water-resistant and durable!

4) The glove leash attachment has been moved to the pinky-side of the glove, making it more comfortable when your gloves hang from your wrist.

5) We upgraded the glove leash.

5) We upgraded the liner construction to decrease bulk and improve dexterity by removing unnecessary material around the fingers. 

6) We upgraded the nylon webbing material, cinch cord caps, and toggle spring tighteners.

7) The RX Pro Mitten has been combined with the former Polar Mitten to make it our new warmest glove or mitten. It now has the V Polar Liner with 300 grams of insulation!

What is the difference between the SX Pro and SX?