If the 4 gallon Birchmeier you purchased then yes, the Birchmeier Flox Backpack Sprayer 2.5 Gal would weigh a little less and might be a better option for you.
The Birchmeier Flox Backpack Sprayer 2.5 Gal. is not battery powered. It is pumped manually.
There are tank markers on the Birchmeier Flox Backpack Sprayer 2.5 Gal. and you should be able to see the amount of water left in the tank. Operate the pistol valve (23) and generate pressure by means of a few strokes on the pump lever. Maintain the pressure by operating the pump lever periodically. There is not a set time you can spray before pumping again as it depends on the pressure pumped but generally you would need to keep pumping throughout spraying to keep the pressure up.
The Birchmeier Flox Backpack Sprayers come assembled for the most part. You may have to put the straps on and adjust them yourself though.
Unfortunately the Duro Mist 1.5mm Nozzle that comes on the Birchmeier Flox Backpack Sprayer 2.5 Gal only puts out a mist spray pattern and does not adjust. The Adjustable Nozzle (Part 28502598) will go from a wide fan to wide cone spray, but not pin stream. We recommend contacing Birchmeirer directly for nozzle recommendations at (800) 675-7485
Birchmeier Adjustable Nozzle - Part 28502598
Yes, we do carry the The Birchmeier Handle (10392201) that can be used with the Birchmeier Flox 10 l (2.5 Gallon) Backpack Sprayer (10956104).