The 6K is a Grade 2 medium-duty cylindrical knob set.

 Unlike other cylindrical knob sets that are made from weaker metals, the BEST 6K Series is constructed of steel or brass to ensure the overall strength and durability of the lock. The 6K is a commonly used lock for non-ADA compliant applications, such as government and military facilities (barrack doors, base housing, etc.) as well as countries that do not require ADA compliance, such as Latin America.