HYDROPONIC BEARINGS High Quality Steel Precision Bearings HYDROPONIC Precision Bearings are constructed in steel, each one housing seven lubricated balls which are designed to disperse the weight of a load and ease tension between the wheels and the axle. Characterized by an 8mm core, a 22mm outer diameter and a 7mm width, these bearings are the industry standard and match up with nearly every skate wheel out there. *ABEC 3 WHITE: For the new skater, who is getting used to the speed and movement of the skateboard. *ABEC 5 RED: For the improving skater, when those initial feelings give way to higher challenges. *ABEC 7 BLUE: For the Am-level skateboarder, who can handle good speed and top progression. *ABEC 7 + SPACERS: Built-In spacers allow for proper alignment and spacing of your bearings. They are especially necessary when subjected to hard carving and sliding, as longboarders do. *ABEC 9 BLACK: For the High-level skateboarder, looking for top performance and a superior quality ride.