There is no such deduction allowed for 2019 returns. The $300 limit on charitable contributions by individuals using the standard deduction is allowable only for 2020 returns (unless Congress extends it).
A statutory method of depreciation allowing accelerated rates for most types of property used in business and income-producing activities during the years 1981 through 1986. It has been superseded by the modified accelerated cost recovery system (MACRS) for assets placed in service after 1986.