BFR I
The BFR I rocket is what we are using for our CATS 120KM altitude attempt.
The vehicle is 7 feet long and 4.5 inches in diameter. It weighs 35 pounds at liftoff. It has a boost phase of 2500 pounds thrust for 3 seconds. The solid fuel motor uses a unique casing consisting of fiberglass and a ceramic nozzle. The complete payload capability of BFR I is 2 kg. It should loft this payload to over 120 km in altitude when balloon launched from 100,000 feet.
Pics of our BFR I rocket under construction: