A Gaslow system comprises one or two “plumbed” in gas tanks that are refillable from some garages throughout UK and mainland Europe and not only saves carrying bottles suitable for each country you visit in UK to exchange a full for empty 6kg propane bottle costs around £40 while I can refill one of my 6kg Gaslow bottles for around £12, a saving of around £28 every time I fill a bottle.
OK, I realise that it will take 36 fills to get the cost of the installation back and I doubt I’ll live long enough to do that but the convenience of just rocking up to a gas line in a garage and filling up as you do with diesel, never having to disconnect a bottle, drag it out to the locker etc., etc., is priceless, as is not having to source Spanish, French, Portuguese or where ever bottles and connectors