Chicago Electric 3/4 Horsepower concrete vibrator.
Make sure your concrete gets set into every nook n cranny in your footing, mold, slab pours.
You want to pour it once and make sure it's right for years to come - no cracks - vibrate it!
Compare to $100 new: https://www.harborfreight.com/3-4-quarter-hp-concrete-vibrator-34923.html