1, 2, 2.25, & 4 Gal Extension - With this extension you can stack multiple packs together! Use in conjunction with a pack mount (RX-PM, RX-PM-DLX, RX-PM-LOX).

1.75 Gal Extension - Use this Extension to stack any Fuel Pack on top of the 1.75 Gallon. Use the standard Extension if stacking the 1.75 Gallon on top of a 1,2 or 4 Gallon Fuel Pack. (alternate SKU RX-EXT-L)

3 Gal Extension - Use this Extension to stack any Fuel Pack on top of the 3 Gallon RotopaX, 3.5 FuelpaX, or 4.5 FuelpaX. Use the standard Extension if stacking the 3 Gallon on top of a 1, 2 or 4 Gallon Fuel Pack.