The Turbo Lube oil bath lubricating systemrotates theroller bearings through an oil bath with each revolution of the wheel. Keeps hub and bearings running cool, reducing friction and wear. These features can actually increase your towing mileage over time. The unique see-thru threaded oil cap assures a leak-proof seal and shows your lubrication level at all times. 75 - 90WT gear oil recommended (not included) Fitswheels with a 2.90 or larger center hole (may not fit all 8-13 wheels) 5 lug with 1 inner/outer bearing Rated at 1250 lbs Sold each - Includes hub, bearings, seals, cap and lug nuts Weight: Approx 8 lbs