Stairtek Unfinished Red Oak Solid Hardwood 1 in thick x 11.5 in wide x 48 in Length Reversible Tread, $54.99 USD/Box, LL Flooring (Lumber Liquidators)

Red Oak reversible box tread features a single ret. Install treads on the step top. Reversible for left or right return use. Mitered return end enhances stairway's open side. Tongue and groove design helps prevent return separation. Unfinished hardwood oak from sustainable sources can be stained or finished to match stair parts. For indoor use only, includes 1-inch bullnose roundover. Made in the USA, available for order online or in stores.