Select field if exit in Proble table other wise select form Itemmaster file?

i want to take balesize from Probale table if exit ,otherwise if Balesize is null in Probale table then balesize will take from Itemmasterfile.

CREATE TABLE #ItemMasterFile(CodeItem INT,Descriptionitem VARCHAR(50),Balesize varchar(50)) 
CREATE TABLE #Probale(BID INT,CodeItem INT,prdQTY INT,Entrydate DATETIME,Balesize varchar(50)) 
INSERT INTO #ItemMasterFile VALUES(1,'A','100lbs') 
INSERT INTO #ItemMasterFile VALUES(2,'B','100lbs') 
INSERT INTO #ItemMasterFile VALUES(3,'C','100lbs') 
INSERT INTO #ItemMasterFile VALUES(4,'D','100lbs') 
INSERT INTO #ItemMasterFile VALUES(5,'e','100lbs') 
INSERT INTO #ItemMasterFile VALUES(6,'f','100lbs') 
INSERT INTO #ItemMasterFile VALUES(7,'g','100lbs') 
INSERT INTO #ItemMasterFile VALUES(8,'h','100lbs') 
INSERT INTO #ItemMasterFile VALUES(9,'K','100lbs') 
INSERT INTO #ItemMasterFile VALUES(10,'L','100lbs') 
INSERT INTO #ItemMasterFile VALUES(11,'M','100lbs')
INSERT INTO #Probale VALUES(10011,1,1,'01-06-2019',null) 
INSERT INTO #Probale VALUES(10012,3,1,'02-06-2019',null) 
INSERT INTO #Probale VALUES(10013,11,1,'03-06-2019',null) 
INSERT INTO #Probale VALUES(10014,10,1,'08-06-2019',null) 
INSERT INTO #Probale VALUES(10015,8,1,'03-06-2019','150 lbs') 
INSERT INTO #Probale VALUES(10016,9,1,'08-06-2019','150 lbs') 
INSERT INTO #Probale VALUES(10017,9,1,'08-06-2019','150 lbs')