Made from buna-n rubber to provide superior resistance against abrasion and water swell. Assortment contains: 2 of each Model No. 35721B (SKU 493791), 35724B (SKU 496707), 35725B (SKU 496715), 35726B (SKU 496723), 35728B (SKU 496758), and 35729B (SKU 496766); and 1 each of model No. 35738B (SKU 493856) and 35739B (SKU 493824). Black. 1 assortment per card.