The factory new Trangia Burners have A crimped connection that sometimes leaks. Solder sealing that crimped connection ensures a leakproof seal.
The Trangia Spirit Burner is the most versatile and user friendly alcohol burner on the market. Besides having a track record of reliable service that spans decades, it also has a couple of uniquely useful features. The simmer ring allows the burner to adjust from full to simmer and extinguishes the flame when closed completely. The twist on cap with o-ring seals the burner so you don't have to empty unused fuel between uses and prevents evaporation - less fuel wasted means less fuel you have to carry. Includes burner, simmer ring, and cap w/ o-ring.