Check the listing for details. R-4D Rocket Engine Connector Plugs & Wires. Condition: New. Listed at 19.99 USD. New! Upgrade your R-4D RCS engine with wires and connectors! These 3D printed plugs and boots (Known in the business as "Cannon Plugs") will make your R-4D more authentic than ever. To be connected to the two top-mounted injectors; see photos in engine listing. Boots will fit 3 or 4 18 gauge insulated wires or 8mm vinyl tubing. If you choose "with wires," you will get approximately 5 feet each of 3 different random colors. If you buy these with the R-4D engine, I will combine shipping. These are the connector plugs ONLY. R-4D engine NOT included! Engine here: https://www.ebay.com/itm/303950684992Note 1: Wires will be random colors - may not be the colors shown in photo.Note 2: I have no idea how accurate these are, but they look good. Note 3: Made of custom 3D printed plastic: will show visible layer lines.