The Ultimate Abyss, the 10-story dry slide on Royal Caribbean's Harmony of the Seas, has a maximum weight limit of 330 lbs (150 kg) per person. This limit is strictly enforced for safety reasons to ensure the guest's speed remains within the "braking capacity" of the slide's custom-designed mats. In addition to the weight limit, there is a minimum height requirement of 44 inches (112 cm). Guests are required to use a specialized mat with a foot-pocket and handles to prevent friction burns and ensure a smooth descent through the dark, LED-lit tubes. The slide drops 150 feet from the Pool and Sports Zone (Deck 16) down to the Boardwalk (Deck 6) in approximately 13 seconds. In 2026, the ride continues to be one of the most popular non-water attractions on the ship, and guests are weighed discreetly at the top before being allowed to board. Those with certain medical conditions, such as back or neck issues, or those who are pregnant, are advised not to ride due to the high-speed turns and sudden stops.