Have you ever heard someone mention what “arrow” a pair Inov-8 shoes has? They are referring to the midesole technology. The arrow number is used to help you decide if the shoes are made for the activity you want to use them for.
Let’s start with the 1 arrow. The Inov-8 F-Lite 195 is a 1 arrow pair of shoes. It has the least possible amount of cushioning available. These are definitely intending for racing and preferably shorter runs. They will be super light, 195 grams in the example of the F-Lite 195, and extremely flat.
The 2 arrow is not all that different from a 1 arrow pair of shoes. These are still intended for racing and have a minimal amount of cushioning. The F-Lite 230 and X-Talon 212 are 2 arrow shoes. You can run a bit farther in these shoes, but you should still consider 3 and 4 arrow shoes for ultra races.
The 3 and 4 arrow shoes are getting into the more “beefier” type Inov-8 shoes. Both can be used for long distance running and training. The 3 arrow has mid level cushioning and the 4 arrow has high level cushioning. Just remember, the more “arrows” means more cushioning and in turn more weight.