This roller has a very unique and rare shape. 

First, the ears.  One end has the type of ear you typically see on 'knobby eared' rollers.  The other end of the float is a flared out ear that's been flatten to where the float can actually stand on end.

The middle of this float has a taper indentation that goes completely around the body.

There's also a thread of glass stuck to the side end-to-end, running the entire length of the float.

Plus this float has the sun-turned purple tint that is highly prized by collectors.

The provenance of this roller is very strong.  It was found in Northern Japan and came from the ex-Woody Woodward collection.