Sold as a set of 4 wheels.
Offset Bearing seat
Radiused outer edge, with Chamfered inside edge
These wheels come in one of 3 Seismic Skate System Formulations depending on your big wheel desires.
BlackOps- The perfect balance of grip and speed. Extremely grippy when fresh, and then buttery smooth predictable slides when broken in. (79a Purple)
DEFCON- This is the Guiness record holder speed urethane. Long lasting grip, with consistent wear. (77a Bubblegum, 78.5a Mango, and 80a Mint)
Premium Clear-Smooth, Fast Grippy, (75a Clear Blue, 77a Clear Purple)
The urethane of the wheel is of course only the surface. These wheels feature that Seismic EC hub, so you get the weight savings, with a acceleration boost, which for getting off of that line or out of the corner might be the difference between winning and not.
All of this combined and it is not a huge surprise that these are the wheels used to hit the world record 91.17MPH in 2017, and an IGSA stand up record in 2010 at 80.83MPH .