Linear DNT00026 Delta-3 Miniature 1-Channel Key Ring Transmitter Go to amazon.com Related posts 8 best linear garage door remote for 2022 FeatureActivates one delta-3 receiverTest/operate ledKey ring includedPower: 12-volt batteryFrequency: 310 MHz DescriptionMiniature key ring transmitter provided with a black case, white button, key ring, test/operate led and 256 selectable codes.