Taking sub oor prep to the extreme Ultraplan ® Extreme 2 self-levels in the worst of conditions Neither rain nor sleet nor high MVER can prevent Ultraplan Extreme 2 self-leveling underlayment from performing. That makes it the best leveler for extreme conditions where there are no environmental controls. No windows, walls or HVAC at your fast-track construction site? No problem! Trust weather-resistant, high-compressive-strength Ultraplan Extreme 2 self-leveler with no limits on moisture vapor emissions.