Where to get bigger reflective sticker

I have a huge RV garage and the small reflective sticker that the light shines on is just not big enough as the door vibrates a lot and moves the red light to much. I need a huge reflective backing probably 12 x 12.

Where can I buy a bigger one?

Yes, for the information on the reflective material, please review following posts:

I got reflectors from Northern Tool & Supply. The reflectors are an amber color and are about 3”x 12”. With adhesive backing. I also have used automotive plastic reflectors, the plastic type that are used on trailers.