Originally Posted by Cat Herder:
Mine have black cords that attach to the underside of the table. A couple of the older kids figured them out but they know if they open it without permission they lose sand play for the day. 
Yes the cords was a big selling point for me but my ds did not take long to figure it out. Although, the first time I opened it the plastic whacked my knuckle and I got a brusie.
I love that it only took one bag of sand to fill it.