I purchased this product to keep our dogs in an enclosed area and off the carpet when they come in from outside.  my chihuahua was too small so he went right through the slats.  he is now 1 year old and cannot fit.  BUT, if you have a very small dog 2 or 3 lbs. you might want to measure him (width) ...  i measured the largest opening between the slats and it measures approx. 3" wide.