Synthesizer Design Letter Set Greeting Card Synthesizer GC-39. I imagined an analog synthezer. For product name and segment LCD number It is also "39" with the meaning of thank you. It is perfect for gifts and message cards. Use thicker paper. The back side is designed so that you can write a message. The envelope is a matte black cotton envelope. It reproduces the atmosphere of a synth hard case and creates a synthesizer feel. Also, the card is postcard-sized. It can be used not only as a stationery but also as a postcard. <GC-39 Black Product Details> 1 envelope (2-inch envelope) 2 cards (postcard size)