I use a 6", I looked at the 4" too but for only a $10 difference I went with the 6".
Type: Posts; User: Host Ray
I use a 6", I looked at the 4" too but for only a $10 difference I went with the 6".
Mitutoyo!
http://www.penntoolco.com/catalog/products/products.cfm?categoryID=378