Isolated chest squeeze that carves the inner pecs.
Squeeze with your chest, not your hands, and control the negative.
The pec fly machine takes the triceps out of the equation entirely, so the chest alone squeezes the handles together through a fixed arc. The stretch at the open position and the hard contraction in front of your chest are exactly the two ends of the range that pressing tends to rush through. The shoulders assist in guiding the arc, but this is the machine you use to make the pecs, and only the pecs, do the work.
It's safer at the stretch and keeps tension on at the top squeeze, where dumbbell flys go slack. Dumbbells free up the path but punish you in the stretched position, so the machine is the smarter default for most.
Open until you feel a real stretch across your chest, without your shoulders rolling forward or straining. Range you can control and reverse smoothly is the limit, not what the machine allows.
You're gripping and pressing with your hands. Soften the grip, keep the slight elbow bend fixed, and imagine hugging with your elbows so the pecs run the squeeze.
