5 1/4 x 2 1/4 x 5 1/4 White Reverse Tuck Folding Cartons. These light-weight cartons are perfect for small parts. Reverse tuck cartons have a pye-lock tuck for positive locking. Meets or exceeds PPP-B-566 federal specification. Die-cut from . 024 fibreboard. Shipped flat to save space. Sold in case quantities. 250/Case.