Metal 【Maximized Space】This bunk bed with trundle occupies a small footprint to maximize space-saving, and the trundle with rollers can be placed under the bed when not in use to save space. 【Safety Design】The 11-inch high guardrail around the upper bed increases safety of the bunk bed and prevents your child from accidentally falling, and 2 side ladders are easy to climb from different angles and positions. 【Robust and Stable】With its sturdy metal frame construction and extra ANTI-TIPPING accessories, this bunk bed is very strong and stable and prevents excessive shaking. 【Noise-Free】We've incorporated custom plastic buckles that securely fasten the slats, eliminating any noise or movement, and ensuring a peaceful and undisturbed sleep. The crafted slat provides excellent mattress support, distributing weight evenly. 【Easy to Assemble】The twin bunk bed with trundle includes the necessary tools for easy home assembly. All parts are clearly labeled and the installation instructions are clear and easy to assemble.