Deluxe Bi-Fold Door Lock, 2 pack

The Deluxe Bi-Fold Door Lock covers the hinged area of bi-fold doors to prevent them from opening and pinching small fingers. Slides back and forth. Special insert lets you adjust for all popular door widths. Includes easy-grip wand for shorter adults and convenient operation. Made from unbreakable polycarbonate for superior strength and fit. Attractive, clear design. 2 pack.

Margaret of North Port, FL Bi-Fold Door Lock
This actually works great. However, the little plastic handle (while a nice touch for short folks like me) will eventually break off no matter how gentle you try to be and you'll have to stand on your tip toes to slide the bar over whenever you need to. But it works like a charm otherwise.
Selena of North Carolina Deluxe Bifold Door Lock
I am just about to order another set of these for my other child's room. They work so well, they are discreet and easy to use, and reasonably priced. Highly recommend!
Tippy of North Carolina Bi-Fold Door Lock
Doesn't look like much, but it works much better than expected. We were really surprised that something so simple worked so well.