A long-short panel on five long-history OKX USDT perpetual swaps (LINKUSDT.OKX, ADAUSDT.OKX, DOTUSDT.OKX, ATOMUSDT.OKX, BCHUSDT.OKX; 4H bars, history from 2019-2020). OKX is 2.4% of the corpus against a 5% quota, long-short is 18% against a 45%+ target, and none of these five series has been used on OKX. The mechanism is volatility clustering plus range release, not momentum ranking. On each 4H close, for each instrument, compute the box width over the last box_bars bars, defined as (highest high - lowest low) / close. A COMPRESSION state holds when that width's percentile rank within its trailing 180 values is at or below squeeze_pct. A position opens only when the bar after a compression state CLOSES outside the box: long on a close above the box high, short on a close below the box low. Orders are market orders at the signal bar's close, which on a 24/7 venue is the next bar's open (the registry's use_equivalent for next_bar_open_fill). Each position gets an intrabar protective stop: a reduce-only stop-market at the opposite side of the box at entry, then trailing at trail_atr x ATR(14) from the best close. It triggers inside the bar in the simulated venue, which is supported natively, and nothing is hosted on the exchange. A failed-break time stop applies: exit if the position has not gained at least 1 ATR within 6 bars (24h). Sizing is risk-parity per leg: risk 1% of equity per trade at the initial stop distance, notional capped at 25% of equity per instrument, at most 3 legs open at once (about 75% gross), leverage 1-2x. The family is a TradingView-style 'squeeze' breakout without the Bollinger/Keltner dressing, here the plain box-width percentile. No supplementary feed is used (L189). Funding is paid or received through the backtest ledger.