HIGH STRENGTH Tthe bottom receiver is rated to tow up to 4,000 pounds GTW. The Combine Maximum Tongue Weight is 400 pounds. (Please Note: The extra top 2 inch receiver is not for towing a trailer) MULTI-USE FUNCTION The lower receiver is used for towing a trailer while mounting a bike rack or a cargo carrier. Top receiver used for accessories only (NOT INTENTED FOR TOWING USE), such as a bicycle rack or cargo tray while towing your trailer or camper without scraping your equipments. It's also widely used on affixed to midsized Boats, small campers, moderately sized trailers and more ADJUSTABLE LENGTH Fit any industry-standard 2 inch trailer hitch receiver, 15 inch overall length, 3 pin holes on the shank allow to adjust the length range at 8 inch, 9 inch, 10 inch when inserted into the receivers GREAT UPGRADE INCLUDE stainless steel bolts and flange nuts, reduce the moving distance of the pin in the hole, better fit, can ues with hitch tightener (sold separately), helps to eliminate the noise, rattle, movement when mounting a bike rack, cargo carrier, ball mount and other hitch accessories. Provide 1 additional clip, double protection, prevent it fell off during towing. CORROSION-RESISTANT Full edge welding instead of ordinary four-point welding, add electrophoresis process before powder coating to withstand rain, dirt, UV damage and other corrosive threats. Ensure a longer service time and making it perfect for long time outdoor use.