Look at the fittings – it's a 20lb female to 1lb male
You'll never be able to fill a 20lb container from 1lb containers – pressure's nowhere near right
This is to connect a 20lb tank to a 1lb-tank-powered stove
Note in the product description:
use gas one’s 50140 converters to utilize your 20lb tanks for your previously incompatible propane appliances
September 21, 2020 at 08:59AM
via reddit https://www.reddit.com/r/preppers/comments/iwrb7i/how_to_use_coleman_camp_stove_with_20_lbs_propane/g63iaf7?utm_source=ifttt