Diamond Boot Factory normally sells their specialty boots for $27 a pair. An offer to buy 120 boots for $19 per pair was made by an organization hosting a national event in Norfolk. The variable cost per boot is $10 and special stitching will add another $1 per pair to the cost. Determine the differential income or loss per pair of boots from selling to the organization. Enter the amount as a positive number. Differential per pair of boots from accepting the special order is