Space Mountain at Disney parks has several strict safety and physical restrictions to protect guests during its high-speed, jerky maneuvers in total darkness. The most prominent is the height requirement, which is typically 44 inches (112 cm) in Walt Disney World and 40 inches (102 cm) in Disneyland. Beyond height, the ride features a "Safety Warning" for guests with pre-existing health conditions: those with high blood pressure, heart, back, or neck problems, or motion sickness are advised not to ride. Expectant mothers are strictly prohibited from riding due to the sudden drops and lateral G-forces. The restraint system itself—a T-bar lap restraint—requires that guests be of a size that allows the bar to lock securely; some guests with larger body types may find the seating (which is low to the ground and tandem-style in Florida) difficult to enter or exit. Additionally, loose items must be secured, and flash photography is strictly forbidden as it ruins the dark-immersion for other riders and can be disorienting.