Provide the weight of the shipment to U-haul Center Of N Syracuse on 2016/9/21.
"U-haul Center Of N Syracuse" is the cust_name; on 2016/9/21 refers to ship_date = '2016/09/21'
SELECT T1.weight FROM shipment AS T1 INNER JOIN customer AS T2 ON T1.cust_id = T2.cust_id WHERE T2.cust_name = 'U-haul Center Of N Syracuse' AND T1.ship_date = '2016-09-21'