Hartz® Gravel Paper. Universal Gravel Paper. Clean & easy to use. Helps trim claws. One size fits all cages. Contents: 9 Sheets, 28 cm x 38 cm (11 in x 15 in). Hartz® Universal Gravel Paper is clean and easy to use. It is ideal for all cages. Providing your bird with Hartz® Universal Gravel Paper helps trim claws and provides grit to aid digestion. Regularly change Hartz® Universal Gravel Paper to keep your bird's cage clean and neat. Hartz® is a trademark of The Hartz Mountain Corporation. Visit our website: www.hartz.com.