We buy the plastic ones from GoWesty and then cover them with
aluminium foil.  We can't tell you how long they last, because we
replace them when we lose them.

B&S
'87 Westy 'Esmerelda Blanc'
SoCal where if we had the sense ghod gave a gnat we'd turn our
sunlight into energy

On Nov 10, 2008, at 4:28 PM, azsun99 wrote:

> I have had good luck with covering the original plastic covers with
> foil tape,
> available at hardware stores. It reflects the sunlight and keeps the
> UV rays from
> directly contacting the plastic.
> Jerry in AZ, where we have an abundance of sunlight, therefore no
> need to save it.