The standard Twin length is 76" but Great Offer Stock only carried Twin at 74" in length. This will be a gap for any Twin bed length.
Recommendation for parents: If you are getting a twin mattress for your child, and I've done a lot of research from *** to ***, you need to get a 7" or 8" mattress. 6" is too thin (can feel the board) on any bed or bunk bed. Also, always check width and length measurements because mattress in most cases will not be long enough to cover it unless you by it from ***.
