This full trundle bed (platform style, meaning mattress only, no box spring needed) has a pull out twin size frame, which is great for sleepovers!  The bottom twin size does pull out completely from the bed.  It's nice because if you have a sleepover, the person on the top doesn't have to step on the twin mattress to get out of bed.  You can push the twin mattress against the opposite wall, so there's a walkway between the 2 beds. Easy to assemble.  It took my husband and I about an hour.  You can choose which side for the twin mattress to pull out on.  I needed mine to pull out to the right, different than the picture.