Air Supersoft 30 and Air Lemon 38 Sponge
Generally speaking the lemon sponges are the variety that have the most bubbles, and thus are the lightest. They are generally easier to sink the ball into. In thinner versions, the ball will go to the blade easily compared to other, denser makes.
Air Zero Sponge
This stuff isn't really so much sponge as it is more of a foam. It's made to absorb the speed of balls, most commonly used with pips. Can be used with inverted topsheets as well. Works well for chopping if you really want to put on the breaks. Topspins are slow and spinny but flat hits feel pretty solid.
*OUT OF STOCK 1.5*
Air Red Sponge 41deg
This is the air red sponge used in Illumina 41deg
Cannon ranges from 0.6 to 2.2 and is the most popular hardness in the AIR range. This is very similar to illumina sponge. Typically midsoft at 36-38deg. Springy with nice feel.