The Firefly 310LID21K is a compact, one-button keychain transmitter engineered as a direct replacement for Linear Delta-3 compatible garage door and gate systems. Operating on the 310 MHz frequency, this remote works with Linear Delta-3 fixed-code receivers and operators that use DIP-switch coding. It’s ideal for replacing a lost or worn-out transmitter or adding an extra remote for residential or light commercial access control. Designed for simple everyday use, the 310LID21K provides reliable, single-door or single-gate control in a familiar, easy-to-carry form factor.
Programming is straightforward: match the internal DIP-switch pattern to your existing Delta-3 receiver or a working Delta-3 remote to synchronize the code—no receiver “learning” steps are needed for this fixed-code protocol. The Firefly 310LID21K transmits at 310 MHz and is intended only for Delta-3 systems; it is not compatible with Linear MegaCode (318 MHz), rolling-code platforms, or Security+ and similar learn-code technologies. Typical applications include garage doors, community gates, and other access points already equipped with Linear Delta-3 hardware. For best results and safety, verify your opener or receiver specifies Delta-3 at 310 MHz with DIP-switch encoding before purchase and programming.