Debate the cost:performance ratio of oversized ceramic bearing pulley upgrades all you want, but there’s no denying that the absoluteBLACK HOLLOWcage is unique, and now it’s available for SRAM eTap AXS derailleurs too, with even greater noise reduction this time around. AbsoluteBLACK says their derailleur pulley upgrade solution is lighter, more aero, lower-friction, AND quieter than stock derailleur cages or other aftermarket upgrades.
What’s not to like?
absoluteBLACK 1-sided HOLLOWcage SRAM derailleur upgrade

There are tons of options to upgrade your derailleur with ceramic bearings or an oversized pulley wheel system to lower the friction in your drivetrain. But only one features an aero-dimpled, one-sided cage designed to flex and a ceramic bearing pulley you can stick your finger through…
AbsoluteBLACK promises faster shifting, silent-running, improved aerodynamics, and the smoothest-rolling low-friction ceramic bearings on the market – all with HOLLOWcage now for your wireless SRAM eTap AXS Red & Force derailleurs.
Tech details – What’s new?
Just like the original Shimano-compatible version, the new absoluteBLACK HOLLOWcage SRAM AXS gets the same dimpled carbon-reinforced single plate cage design that curves from the outside of the upper pulley at the derailleur to the inboard-side of the hollow lower pulley.
AbsoluteBLACK claims the more flexible design (than a conventional 2-plate layout) actually lowers drivetrain friction, while the upper pulley remains perfectly positioned for precise shifts.