Query To Return Records Containing 2 Characters In A Field

I have a field in Access 2010 called Section Number which generally holds two characters. The characters can be numbers, letters, or a combination. Examples are:

01
X1
KA
40

Sometimes this field holds three characters, such as:

01a
02b

I want to write a query that returns only the Section Numbers that contain two characters. The instances where the field holds three characters are too numerous and changeable to use a parameter that says, for example: not "01a" and not "02b"

Is there a way to write a parameter that means "not Section Numbers of three characters" or "not Section Numbers of more than 2 characters"?