It's a complete kit made for Schwinn Meridian Trikes by staton-inc.com, comprising custom mounting hardware, custom gearbox with 18.75:1 ratio, & a Honda GX35 4-stroke motor. I'm getting 25mph all day, & 116mpg. A bit pricey compared to what else is out there, but you get what you pay for, & it all bolts together great, Here in AZ only 48cc & below are street legal with unlicensed riders - so all the 49cc's flying around everywhere are all illegal without a Driver's License.
Check out their website for mounting pics, also all the different kits they have, & for different brand trikes also. They also do two wheeler kits, & some complete bikes/Trikes I think.