For use with: 2023+ KTM, Husq, GasGas, (24' only) VHM is widely regarded as the leader in custom head and insert design and modification. It should be so surprise that we have aligned with them to offer their amazing pistons, as well as their outer heads and interchangeable inserts. We have tested a variety of inserts and have found a few that work amazingly well with specific octane. Here are the specifications for what we have tested and have proven to work well. ** Keep in mind that the 12* inserts will also need a 12* piston to go with it and can't be used with a stock flat top piston.**