These are the standard 4" split carbides that come with a new Sidewinder.
I have run these in the past on other Sidewinders I have owned and found them to be very predictable, easy to steer and do not seem to allow the sled to "dart."
I bought the sled with under 30 miles and the owner to the dealership rode the sled once to dinner putting on just over 30 miles.
It is up to the purchaser to confirm the bold pattern matches the bolt pattern on the ski's. I have provided the tape measure pictures for this purpose. Please let me know if additional pictures are required.
A set of these runs $150. I am selling these for $75 plus freight.