As the name "o bokken" implies, this is larger than a standard bokken. (Quick Japanese etymology and swords lesson: "o" something means big something. An odachi is an over-sized katana. A nodachi is a muckin' huge katana. "O" and "No" are sometimes interchangeably used, but this is incorrect. Of course, size is somewhat relative ...)
Anyway, as I was saying, this is an oversized bokken. Good fun for oversized people like me to whom standard sized bokken feel just a bit too short and light. (Digression - back when I was practising aikido and kenjutsu on days opposite SCA fighting practices, the bokken always felt way too small for me, especially compared to the rattan nodachi I was regularly using at the time - so I would work out with a triple-weight bokken in class, a specialized bokken called a suburito. Even though class space was crowded, I always had plenty of room when swinging that monster. The drawback was that no one wanted to work with me on partner drills. Such is the life of a sword lunatic).
Anyway, I got off base again. This heavy grade polypropylene bokken is longer, thicker, and heavier than the standard indestructible bokken. Good for the days when you want it long, thick, and indestructible.