I have this set up for my 4 month old mini Aussie Shepherd and have used it for the past 2 months.  When I leave for short periods of time (2-3 hours) I place her in the pen with her cuddle bed, and she is perfectly content.  With this pen, I dont have to crate her, and she has room to move with no worries about leaving her to run free in the house alone )  I also have the double door matching crate with attaches easily to the pen if necessary.