SkyRider is a Wind Directional Cap (also known as Roman Helmet, Rooster Tail and other names). The top helmet of the cap can freely rotate around its shaft. When wind blows, the fin aligns the hood against wind and front skirt will divert all air streams over and sides of the cap along with rain and snow solving wind related downdraft problems. Also, when wind flows over the cap this way, it creates low air pressure over the flue due to the speed difference of air inside and outside of the flue. This effect helps the flue to draw air better acting as if your flue is taller. The streamlined shape of the cap slices through air with very little resistance and it can withstand very strong winds. Our caps have been tested in Alaska exposed to natural wind speeds of 70-80 mph (and that is not the limit) without having any problems while doing its job. The shaft of the SkyRider is not ball-bearing and it does not have to. Exposed to hot ashes with creosote, ball-bearing would be jammed quickly. The shaft of this cap is not under heavy load and designed for a lifetime. No special maintenance is required, clean it as often as you clean the flue. Use graphite or nickel based anti-seize lubricant. The anti-seize lubricant has the powder of graphite or nickel mixed in and it works as ball-bearing. You can buy it in any car-parts store as anti-seize for spark plugs. It is designed for temperature range from -65°F to +2400°F. Never use petroleum grease as it will cause jamming.