This is a very cool new gadget that was given the editor's choice award from Backpacker Magazine in 2010. It works by inserting a cheap disposable lighter and pushing a button to produce a hot jet of fire. I believe it only weighs around 2 ounces.
This is taken from the Soto website
Electron ignition! Strong wind-resistant burner.
Disposable lighter becomes a wind-resistant burner.
The Pocket Torch uses disposable lighter fuel.Light the Pocket Torch with a disposable lighter and produce a flame that reaches temperatures up to 1300°C (approx. 2,300 °F).
The Pocket Torch becomes a powerful, wind-resistant burner.
A disposable lighter increases it lifespan by 60% when used with the Pocket Torch.
Size: 110 x 60 x 23 mm (4.3 x 2.4 x 0.9 inch)
Weight: 50g (1.8 oz.) without disposable lighter
Burner Diameter: OD 14 mm (0.55 inch) ID 12 mm (0.47 inch)
Flame temperature: 1300°C (Approx. 2,300 °F)
Flame size: Diameter 3 x 12 mm (0.1 x 0.47 inch)
Flame shape:Superfine centralized flame
Burning time:Approx. 20 minutes (per disposable lighter)
Fuel cartridge:Disposable lighter