Will it be effective below freezing point? Does it accept Primus-style self-sealing canisters? TIA

Yes & no. Yes if the fuel canister is near full and yes at higher altitude because of lower atmospheric pressure. No if the cannister is less than half full. None of the cannister fuel stoves are great for cold weather. The more volitile gas cooks off first and the remainder just doesn't cut it in the cold.
Works with any of the small screw-top canister fuels. My understanding is the screw size and pitch are standardized, plus the canisters all come out of one of just two factories.
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