Adjustable Height for Secure Fit: This Twin Size bed rail set features multiple height settings to accommodate mattresses up to 12 inches thick. The adjustable design ensures a secure fit for different mattress thicknesses. Stable Four-Point Connection System: The Twin Bed Rail utilizes a four-side attachment method with an optional headboard support rod. This design provides steadier support than basic single-connection rails and helps minimize movement during use. Universal Bed Size Compatibility: Designed to work with most standard U.S. Bed sizes including Twin, Full, Queen, King, and California King.