Which seat is the best for me?
The different kind of seating systems:
Rail: the seat has a rail underneath and is compatible with railed seatposts.
Pivotal: the seat has a hole in the middle, covered by a patch and it has a bolt in it for the seatpost.
Stealth Pivotal: the seat has a bolt underneath and is can be screwed into the seatpost from the side, compatible with stealth pivotal seatposts only.
Tripod: the seat has 1 bolt and 2 mounting points. Sold on customer request.
The sizes of the seats:
Slim - has a thin layer of foam on it. Smaller and lighter than the others.
Mid - has a thicker layer of foam, better to grab.
Fat - has the thickest layer of foam, good to save your bottom when you crash and easier to pitch it with your knees.
Flatland - special style of seat design for flatland riding purposes.
Pro-Tipp: the normal pivotal seats are also compatible with stealth pivotal seatposts but the bolt will be outside the seatpost. But it works.