I first tried the medium. It was a lot softer than what i like. It bubbled a little but i could have dealt with it. So then i tried the hard. Holy cow the 40D is the hardest ive used! You could knock them out if u hit them in the head with a bait! But bubbles were a nuisance. I Then tried the medium hard and liked the hardness but got the bubbles. I imagine i could learn how to use it and make it work if i would take the time. Its just hard to change plastics when i know the cycle times down with what im using!