Envy Colt forks are pulled straight off of our best selling entry level scooter, the Envy Colt. Colt forks are a durable steel fork and are more affordabler than comparable IHC aluminum forks because they don't have to go through a machining process. Simply put, the Envy Colt forks are the most affordable quality IHC forks that money can buy. Make sure that your bars are IHC compatible. Envy PRO SCOOTER FORKS are an aluminum pro scooter fork that work with the following types of compression: IHC. Colt 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. Envy Colt forks are durable forks and can be ridden on the street or at the park. The Envy pro scooter forks are compatible with the following wheel diameters: 100mm,110mm,115mm,120mm,125mm. Envy pro scooter forks are ONLY compatible with wheels with a 24mm core.