The 18V ONE+™ Chemical Sprayer Backpack Holster is compatible with both the RYOBI 18V ONE+™ 1 Gallon and 2 Gallon Chemical Sprayers. Designed with durable elastic mesh materials for increased comfort and support no matter how long you work. Slip your existing RYOBI 18V ONE+™ 1 Gallon or 2 Gallon Chemical Sprayer into this backpack holster and adjust the carrying straps for convenience and maximum comfort.