Sensor lense?

[Marco123]

Is the sensor lense materials of zirconia and sapphire the same for all three models of watch?
Does the SS watch have better materials used similar to what they do for the face glass?
Thanks.

 

[Lennyvalentin]

The Sport model has a plastic (Apple calls it "composite", because that sounds better) back, with a (probably vapor deposited) hardcoat across it to protect against scratches, much like the plastic lenses of eyeglasses get these days.