I have never ever worked with a pin that is this thin and I'm telling you, I never will again. Hold onto your hats, I SEW over them! That's right! I said it! They are that thin. They are very, very thin, almost hair-like and super sharp. You can see the size in the photograph. Karen suggests, and I concur, that because the head on these pins is so small we like to spill the pins onto a piece of light colored felt, making it easier to pick them up. They are also easier to keep track of this way — dropping old fashioned straight pins is one thing, losing these can be pretty easy — and painful! BUT IT'S SO WORTH IT! There are 45 pins in each little plastic tube.