Air Lemon 35deg 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 - New stock/thicknesses
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.
Air Red Sponge 41deg/35deg
This is the air red sponge used in Illumina 41deg. Denser for short game control but still softens up to loop nicely when broken in.
OUT OF STOCK 2.1
Air Cannon
This sponge has changed from what it used to be. Now it's pretty hard and kind of dead-ish, more like a traditional Chinese sponge. - OUT OF STOCK 2.2