score:5
They are called "gassboks" (gas can) in Norwegian.
I doubt that you'll find any at the airport, but if you are going by train from the airport to Finse, you'll have to change trains at Oslo Central Station and there are plenty of outdoor shops in downtown Oslo, which all are likely to have these on stock.
If the shop you're linking to is sold out, there is a Clas Ohlson store just a few houses down the street in Torggt. 6 (Oslo Sportslager is in Torggt. 20). According to their web page, they have the gas cans on stock.
Upvote:3
For anyone interessted, the kind of connection on these fuel canisters / gas cans is actually called a "Lindal Valve"
We where able to get them at Oslo sportslager
Upvote:4
Went to Norway last week, did a lot of research to find gas canisters. We landed on Rygge on a Saturday evening, and there is a Shell not far from the railway station with a seven eleven, we bought them there. When we wanted to drop off our spare gas at the DNT hut in gjendesheim, the guy there said they have about 100 spare ones of those lying around, so if you're passing by a staffed DNT hut, call them first to hear if they have some lying around :-)