Lincoln Electric rubber backing pad for use with 4-inches abrasive sanding discs. It is designed to offer favorable conformity for medium to heavy grinding. Designed to maximize stock removal. It is balanced for even disc wear. It features a slotted hub design that helps draw in cool air, reducing heat buildup. This backing pad is compatible with coated fiber discs. 1-1/2-inches spindle nut. M10 x 1.50 hub thread.