These clear rollers appear to be more recent productions but are probably authentic used fishing floats.  I've been told they could have Chinese origin.

This type of float have four distinguishing features:  1) color is clear, 2) distinct fine mold line, 3) higher quality glass (without many bubbles), and Hokkaido roller like shape.

There's a nice brown swirl in the seal of this particular roller.

It measures about 5 7/8 inches in length.