SHERLINE Trailer Tongue Weight Scale SKU 5780 Combo! Installed gauge.:Scale of 0-2000 Lb and 0-900 kg (Inner Scale) Spare gauge: LM2000 Scale of 0-2000 Lb. and 0-900 kg (Inner Scale) 9/16" open wrench is needed (not included in this package) to change between gauges. The fast and easy way to measure tongue weight for safer towing. Just place under ball receiver or under jack stand to measure tongue weight directly in pounds or kilogram (The scale has both Lb and KG. )