A mechanism that banks a share of a trade's peak profit once it crosses a threshold — so a winning trade can't round-trip all the way back to a loss.
Without any intervention, an open trade can go from a nice floating profit back down to breakeven, or past it into a loss, if the market reverses before the take-profit is hit. The profit lock addresses that directly: once a trade's floating profit crosses a trigger amount, the system locks in a guaranteed floor — a percentage of that peak — so a reversal can only give back part of the gain, never all of it.
The lock guaranteed $18.53 the moment it triggered. The trade didn't need that floor in the end — it kept running and closed at $150.00 — but the guarantee was there the entire time it was open.
Critically, the lock doesn't cap the trade. If price keeps moving favorably after the lock engages, the trade stays open and can close for far more than the locked floor. The floor only matters if the market turns — which is exactly when it earns its keep.