Hexagonal shaped jet with K stamped on the side for kerosene (paraffin if you are a Brit), for the pre-2012 MSR WhisperLite International stove.
Part Number: 419609.
This stove has wire legs and comes with a K Jet. If it didn't include the K Jet when you bought it then it is probably not an International and cannot burn paraffin/kerosene.
Shaker Needle not included.