The bottom line: This year Congress is running a large "bonus depreciation" special on cars weighing more than 6, 000 pounds, such as the Cadillac Escalade and Nissan Armada.

WSJ: Tax Report: The New Tax Breaks for Business Autos

The liners, weighing perhaps five ounces or less, would go under a pitcher's cap and help protect against line drives that often travel over 100 mph.

NPR: Jays' Happ Hit In Head By Line Drive, Carted Off