drinking water pump is used for 3,5 gallon bottle,it is a perfect drinking tool.

electric drinking water pump

1.Material:ABS, P.E, food-grade,without smell or toxic material to ensure water
quality.
2.Can be used with 5 gallons water bottle, 
Neck Dia. of the bottle:  55mm(standard)

Advantage:
1.Battery operated.  (2*LR20,D Size) 
2.No drips or leakage.   
3.Great for the shed, cabin, camping, etc. 
4.Dust-proof outlet.   
5.Spare brush for easy cleaning.  
6.Stable liquid flow.

manual drinking water pump:
- Heavy-duty vacuum action (works like a pressure pot)
- Dispenser as quickly or as slowly as you like: simply push down on the top of the
   pump
- Unique adapter allows the pump to be mounted to any bottle 
- No dripping or leakage
- For efficient dispensing of room temperature water directly from 19L or 22L bottles
- Made of durable food-grade plastic
- Easy to install and remove
- Clean inside of plastic pipe with brush after long use

You can use manual water pump to drink gallon bottle water outside