Amazon.com : Continental 26" x 1.75-2.5 Mountain Bike Inner Tubes with 42mm Presta Valve (Set of 3) : Sports & Outdoors
Zol Mountain Bike Bicycle Inner Tube 29"x2.8/3.25 Presta Valve 26.5 mm (2) - Walmart.com
Amazon.com : 2 Pack CST 29 Inch Bike Inner Tubes for 29x1.75/1.95/2.0/2.1/2.125/2.3 inch Schrader Valve SV 48mm Bicycle Tires Anti Puncture MTB Bike Interior Tyre Tubes Replacement : Sports & Outdoors