Oval chainring from AbsoluteBlack specially made for Shimano 12 speed chains. Does not fit Shimano cranksets, but does fit the following:

SRAM XX1, XX1 Eagle, X01, X01 Eagle, GX Eagle, NX Eagle, SX Eagle, X1, X0, X9, X7, S2210, S1400, Descendant, Stylo, Truvativ AKA and all DUB cranks.Cane Creek eeWings. GXP and BB30.

With 3 mm. offset to fit only boost frames