DEI markets aftermarket alarm systems under several different brands, including Avital. One common remote transmitter used with Avital alarm systems is a 4-button remote with FCC ID EZSDEI474S and part number A-474L on the back of the case. Remotes Unlimited has discontinued this remote transmitter, but we still have a few in stock. You can see and buy this keyfob now at this link.
Avital also made a 3-button remote that used similar technology. The 3-button version of the keyfob had the same FCC ID number, EZSDEI474S, but a different part number, A-473L. Remotes Unlimited no longer stocks the 3-button Avital remote, but we do sell a compatible 3-button remote that has no logo on the front. See Avital 3-button remote and available replacement keyfob at this link.
You can program your Avital alarm system to accept a replacement remote control using the valet switch.