Error Code : 1064

[Fred Knaut]

Getting the following error:
Error Code : 1064
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'END' at line 5

With the following trigger:
CREATE TRIGGER `polymer`.`Avail_Weight`
BEFORE INSERT ON `polymer`.`inventory`
FOR EACH ROW BEGIN
SET NEW.Available_Weight = NEW.Raw_Weight - NEW.Processed_Weight
END ;

Why?