Richell Mobile Pet Pen: * Recommended for dogs 8 to 18 lbs. * 1-1/4 space between wire slats * Wire door is 9-3/4"W and 13-3/4"H * Wire is 7 gauge (.144") * Slide-locking system on door and wire top * Latch-locked base provides additional security * Lockable casters provide easy mobility and safety; removable wire top and base; easy to assemble; instruction manual included