4.0

It took a lot of effort to get the knobs on to my 2006 ER-6N - at first I thought the pitch was wrong when they got stuck a couple of turns in. I called BikeBiz and confirmed they should fit my model. I had to scour the inner threads out and lightly sand the knob threads, and eventually managed to get them on the bike. No concerns about them ever backing out, and they look good and are a good size for guiding the rear stand in.