COVID boredom engulfed me, so I purchased a "waterproof" RICETOO geared system from Amazon ($300 plus tax, free shipping). The kit included torque arm, rear light, front light and brake shut-off parts (for those who use them) as well as the motor, 22 Amp (AIR) controller thumb throttle, PAS unit and a nicely lit display. Installation on an early 90's Diamondback Axis MTB was easy with the biggest challenge being hiding excess wires. The package came to 36 pounds without battery and with a 52V 14 ah Luna battery goes 25 mph with 180 pound rider. The kit seems decently thought out, manufactured adequately and saved me from purchasing a similarly-equipped bike just for something different to ride.