The scooter industry is always changing. Wide wheels are becoming ever more popular among pro riders so Root introduced the Lithium forks, which are compatible with both 110x24mm and their own Lotus wheels, which have a 30mm wide PU but 24mm core. The Lithium forks will NOT work with 120x30mm wheels that have a 30mm core. IHC compression is built directly into the Invictus forks so all you need is a bars with a slit and a clamp and you're ready to roll. Root Industries PRO SCOOTER FORKS are an aluminum pro scooter fork that work with the following types of compression: IHC. Lithium forks are IHC forks so the compression is built directly into the forks. A compression bolt on top of the forks compresses a shim onto the headset, eliminating the need to purchase external compression. Since you do not have to purchase compression AND forks when you buy IHC forks, IHC compression is an affordable and very popular compression system. Root Industries Lithium forks are durable forks and can be ridden on the street or at the park. The Root Industries pro scooter forks are compatible with the following wheel diameters: 100mm,110mm,115mm,120mm. Root Industries pro scooter forks are an extremely versatile fork and are compatible with any of the following wheel core widths: 24mm,26mm,28mm,30mm. To swap out different width wheels, you will need compatible spacers for the wheel width selected.