Google has just unveiled more options for its previously announced prescriptions glasses. The $225 upgrades are now on offer to Google Glass Explorers.

The frames are made from super-light yet super-strong titanium and come in four new frame styles with two different shade options.

READ: Google partners for Glass prescription, fashion and sports lenses

The four styles are Curve, Thin, Split and Bold. The Glass itself is then attached using several screws. The designs, all done in-house, aim for simplicity. Some of these also attempt to help hide Glass itself.

The new frames and lenses go on sale today in the US where America's largest optical health insurance privider, VSP, is helping Google to offer subsidised frames and lenses.

READ: OpticsPlanet's Wetley GGRX becomes first prescription lens adapters for Google Glass