The Hafele 271.92.202 Bed Kit is designed for a Double/Full size mattress. Here are the standard dimensions and considerations for fitting a mattress to this frame: Standard Double/Full Size Mattress Dimensions: Length: 75 inches (190.5 cm) Width: 54 inches (137 cm) Thickness: The thickness of the mattress can vary based on personal preference and mattress type. Most mattresses range from 8 to 14 inches in thickness. However, you should consider the following when choosing the thickness: Bed Frame Design: Ensure that the thickness of the mattress is compatible with the bed frame's design, especially if the frame has side rails or a headboard/footboard that might restrict the space. Comfort: Thicker mattresses (10-14 inches) tend to be more comfortable and durable but can be heavier and more challenging to handle. Support: The bed frame should provide adequate support for the chosen mattress thickness. Recommendation: For the Hafele 271.92.202 Bed Kit, a standard Double/Full size mattress with a thickness between 8 to 14 inches will fit well and provide a good balance of comfort and support. Always check the specific frame's guidelines or manufacturer recommendations to ensure compatibility.