I did find out that it is a GX9000

this was my reply from Genie when I asked them
"Under the light cover you have a little white sticker. top row is WK YR P1 Bottom row is the date of manufacture. If the unit is 1997 and after, you can use the GMI-3 mini remote. If before 1997, you will have to use a standard size intellicode remote. Thank you

I think you should call your local Genie dealer and ask him. They will know.

Thanks for your reply. It is pre 1997 :(

You might want to check with Radio Shack. They advertise a universal unit for $9.97 that just may work for you. The model number is G6MR and the catalog number is 61-133.