This the Olympus TCON 17, this is basically the same lens as the B-300. This is an excellent lens for a 1.7x. The lens has a 55mm camera end and NO threads for filters. This lens runs around $100.

This site will give you more info and you can compare the TCON-17 and B-300
http://www.b-300.com/compare3.html

By Bill Huber