In a craft I am doing, an exact amount of product is needed each time. It is very tedious to to weigh 24gm. each time. I am constantly adding just a little more goo and then removing some, and then I had removed just a bit too much... Now the plunger is removed, the goo is pushed down with a chopstick, and repeat till full. Plunger reinserted and all ready. And now it just takes that little plunger push to the next desired line and Voila, the exact amount is deposited each time. Having been a R. Psych. N. and a RN, I know needle barrels and these are just fine. Good price and no metal needle part to discard. Perfect! Review written by La Wife