The bread and butter of horseshoe triceps.
Don't let your elbows drift forward, lock them in place and move only at the forearm.
With elbows pinned to your sides, pressing the bar from chest height to full lockout isolates the triceps in the cleanest way possible, the cable keeps tension on them through the whole arc, including the squeeze at the bottom where free weights go light. Everything above the elbow stays frozen, so the triceps have no help and nowhere to hide. It has earned its status as the default triceps isolation, easy to load, easy to progress, brutal when done strictly.
Almost always drifting elbows. Once they creep forward, your lats and shoulders start pushing the weight down and the triceps go along for the ride. Pin the elbows to your ribs, lighten the stack, and lock out fully with a one-second squeeze.
Both hit the triceps, the rope lets you spread your hands apart at the bottom for a harder squeeze, while a bar usually allows a bit more load. Rotate them over time, the exercise is the elbow lockout, not the attachment.
A slight forward lean with a braced core is fine and keeps you stable against the stack. Hunching over the bar and pressing with your bodyweight is not, if your torso moves during the rep, the weight is too heavy.
