Murphy Construction Materials Company has a sales office that sells concrete culvert pipes to property developers. The sales office is a revenue center and prepares a monthly responsibility report. The partially completed responsibility report is provided. Revenue Center Responsibility Report

Product Type	Actual Sales Revenue	Flexible Budget Variance	U/F	Flexible Budget	Sales Volume Variance	U/F	Static Budget
40 inch	$31,700			$30,750			$40,800
36 inch long	40,150			42,200			33,000
36 inch short	36,200			33,100			31,000
32 inch	19,100			20,000			28,400

The company uses management by exception to address flexible budget variances. On which product type would the company first focus?