Link to FlatOut tube/tire sealer FlatOut Tire Sealant Trailer Formula, Prevents and Repairs Flat Tires, Seals Leaks, Contains Kevlar, 32 Ounce Bottle, 1Pack https://a.co/d/70AIqpX

Link to tire tubes 20x4 with steep stem
2 Pack 20" Fat Tire Tubes 20" x 4.0" TR4A40L Valve Heavy Duty 20" Fat Bicycle Tubes Compatible with 20x4.0 20x4.2 20x4.3 20x4.4 20x4.5 Electric Bike/Mountain Bike Fat Tire Tubes https://a.co/d/6zLBDxf