An isotope is an atom in an element that has the same number of protons, but a different number of neutrons in the nucleus. Radioactive decay is the amount of time required for an atom and its contents to decay. Half Life is the time required for an amount of radioactive material to be decrease by one-half. It generally decreases by about one half each period of time. The isotope of 44 ti is for titanium, and it has a half life of 160 years. The reason that it has such a long half life is because Titanium is one of the strongest metals known to man. If you are into science, you would want to purchase this because if you got a bunch of different elements and isotopes, who knows what you could combine and make. If you are into making new elements, this is for you!