Sugino's new "Zen" full skirted (not cut away from the bolt circle) track chainrings are available in sizes 46 through 55 for 1/8" chains. They fit all cranks with a 144 mm. bolt pattern. The Zen tooth profiles have been carefully contoured to ensure the smoothest possible engagement/disengagement with chain links and rollers. For those who care about such issues, Zen rings bear the NJS logo for keirin certification.
Shown below is the "tails" side of the chainring. The inner web is extensively relieved, making these chainrings surprisingly lighter than they might at first appear.