It set the average ad valorem tariff rate at 50%, the highest ever.  
This bill crippled the Welsh tin plate industry and led to election defeat for the chair of the House Ways and Means Committee who sponsored it.  Benjamin Harrison was instrumental in conjuring up Republican support and it received votes from Western and Southern Democrats in exchange for Republican support of the Sherman Silver Purchase Act.  The first act of its kind to provide for reciprocity, the Wilson-Gorman Act of 1894 modified it.   It set the average ad valorem tariff rate at 50%, the highest ever.  For 10 points -identify this 1890 Tariff named for an Ohioan who became president.
This bill crippled the Welsh tin plate industry and led to election defeat for the chair of the House Ways and Means Committee who sponsored it.  
McKinley Tariff Act of 1890