Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_1251878_1 ( width VARCHAR, frame_size VARCHAR )

### Question ###
what's the width with frame size being 4.5k

### Accurate SQL ###

SELECT width FROM table_1251878_1 WHERE frame_size = "4.5K"