This 3mm offset oval chainring transforms any Sram crank into a Boost148 crank. Boost and not Boost cranks are identical, existing offset is only created by the chainring. So you can use any Sram crank with this chainring for Boost148. The regular absoluteBlack GXP oval chainrings have 6 mm offset, this one has 3 mm.
The oval shape has no negative influence on the pedalling rhythm. The oval shape allows a more efficient power transmission and relieves the knees.
A 28Z oval chainring has an ovality of 26/30Z and is perfect for someone who currently drives round chainrings with 27 or 28 teeth.
A 30Z oval chainring has an ovality of 28/32Z and is perfect for someone who currently drives 29 or 30 tooth round chainrings.
A 32Z oval chainring fits perfectly for someone who drives a round chainring with 31 or 32Z. While it feels like a 31 tooth chainring, it develops speeds equivalent to a 34 tooth chainring.
A 34Z oval chainring has an ovality of 32/36Z and is perfect for someone who currently drives round chainrings with 33 or 34 teeth.