The Maxit Corporation has a standard costing system in which variable manufacturing overhead is assigned to production on the basis of standard machine-hours. The following data are available for July:

• Actual variable manufacturing overhead cost incurred: $26,360
• Actual machine-hours worked: 3,300 hours
• Variable overhead rate variance: $5,970 U
• Total variable overhead spending variance: $8,360 U

The variable overhead efficiency variance for July is: