The Empire® 12 in. / 300 mm True Blue® combination square (E250IM) has precision machined working surfaces and a head with rational dimensions for a quick check of common measurements. The square has the BLADE-LOCK™ self-aligning drawbolt allowing quick adjustments with a secure hold. The DUAL-PITCH™ True Blue® vial al Empire E250IM - 12 in. / 300 mm True Blue® Combination Square