Carper 300 Keychain remote 300mhz 10 dip switch How do I know if this Keychain remote is the right one for me? 1. Frequency: Check the back of your current remote to make sure the frequency of the remote or garage door opener is 300mhz (megahertz). 2. Dip Switches: Open the battery compartment on your old garage door remote and look to see how many dip switches (tiny switches in a row) it has. If your old remote had 10 dip switches and is 300mhz, then it's a match for this remote. If you don't have your old garage door remote, you can also look to see how many dip switches are on the back of your garage door opener (the overhead unit in your garage). The number of dip switches on the back of the opener is the same as on the remote. Mini garage door opener remote with built-in flashlight, key ring and 12V battery included Mini ""key chain"" size (2"" by 1"") Key chain and convenient surface mount kit included Compatible with the following garage door opener manufacturers: Multicode, Multi-Elmac (10 Dip Switch Binary Remotes)