So this little syringe in the picture may look nefarious, but what it contains is a cannabis concentrate known as RSO or Rick Simpson Oil. Rick Simpson being its creator, who was a Canadian cancer patient, and who is credited with discovering the technique. He created RSO by using isopropyl alcohol to extract the oil from the buds by essentially dissolving the trichome heads' (where the THC lives) bond to the plant matter. That process is at the heart of every concentrate - how did we get the trichome heads full of the oily good stuff away from the plant matter.
Now, while many folks do successfully make their own RSO at home, it can be dangerous, both in execution and in trying to be absolutely sure that all the alcohol is removed from the final product. Luckily there is another way, which is both easier to do at home and safer.
FECO stands for Full Extra Canna Oil. Plenty of people argue that not only is it the easier one to make it at home, but is the superior product anyway. Really the only difference is you use very high proof grain alcohol, the highest you can get. In most places that's 190 proof. However if you live in a state where you cannot buy alcohol that strong, you can purchase food grade alcohol on places like Amazon that will work just as well.
Some people argue that not only is FECO easier to make at home, but is also the superior product. The most common way of consuming FECO or RSO is by eating it in some way. Either straight out of the syringe, on toast like jam, or mixed into edibles. We'll get more into all that another time. But since FECO is made with food grade alcohol, people have the perception it is the safer product. Honestly I've used both and they're pretty similar in taste, effect and usage. FECO is almost exclusively used in home extraction, and RSO is what is available in most dispensaries, here at least. A .5mg syringe of RSO runs about $25, which makes them really easy to pick up on a weekend dispensary run to make some homemade edibles with.