These are replacement HEAVY DUTY earcup yokes for the Bose X aviation headsetMade in the USA, they are far stronger, longer-lasting and less expensive than other aftermarket or the factory versions. They will last the life of your headset, guaranteed.BOTH SIDES INCLUDEDMOUNTING SCREWS INCLUDEDThey are made of a high-end annealed carbon fiber-reinforced composite that is much stronger than other resin-based aftermarket parts and exponentially stronger than the cheap plastic used in the original part. The design has been totally reworked using SolidWorks software, the same software Bose used with designing the original headset. They are then produced by a company located in the US who are experts with manufacturing aerospace parts. They simply will not break even under extreme stress (the rest of the headset will fail before these parts do - we dare you to try to break them!) They are not weakened by UV exposure or age.Simple install using just a screwdriver. Includes stainless steel Phillips mounting screws (4 for the mounting brackets, 2 for the cord retainers)Lifetime no-hassle unconditional replacement guaranteeA portion of every sale is donated to the National Fallen Firefighters Foundation