This wonderful twin over full bunk bed provides for a bit more room in the bottom bunk. The full bunk bed on the bottom being wider, extends past the width of the twin upper bunk. This "extension" can be ordered either right or left. Standing facing the footboard, a right extension will extend to the right, a left extension will extend to the left. Both the upper and lower bunks come with a "bunky board" mattress support. Maximum recommended mattress thickness for the top bunk is 6". Skilled craftsmen patiently skip peel the posts and spindles by hand using old-fashioned draw knives. Careful assembly by hand ensures the bed will last a lifetime. Some assembly required. 20-year limited warranty included at no additional charge. This item is shipped unfinished and we recommend that this item be finished with a wood finish to preserve it.