Write SQL query to solve given problem: For the on going assembly item Component ID No. 494, what's the Unit measure for it?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T2.Name FROM BillOfMaterials AS T1 INNER JOIN UnitMeasure AS T2 ON T1.UnitMeasureCode = T2.UnitMeasureCode WHERE T1.ComponentID = 494 AND T1.EndDate IS NULL GROUP BY T2.name