I got a bunch because they were on sale cheap. For those not familiar with them, they are a 'glass filled ryonite' dagger. The round handles are about 1/2" diameter with deep grooves spaced about 3/4" apart. The blade is double hollow ground so the blade cross section is a diamond shape with four concave sides. The point is shaped like a Roman short sword (pointy bullet profile). That point is surprisingly sharp. You can see them at
http://members.tripod.com/~Newt_Livesay/SPECIALS about 2/3 of the way down the page.
The darts are only for thrusting, not cutting. Very lightweight and suits its purpose as a last ditch defensive weapon well. It's nice that it comes in a sheath that has no metal on it. Sheath is just a piece of kydex folded over. It has no rivets, but still secure since the dart weighs almost nothing. These babies are magnetically & metallurgically invisible and lightweight enough you can stick them anywhere; sock, shorts, taped to forearm or SOB or anywhere else, neck carry, etc.
Messing around with one I broke the blade off without a lot of lateral pressure. That got me thinking that you could file barbs on the edge of the blade facing the rear. That way, after you thrust the blade hilt-deep into the target you could crank the handle sideways to snap the blade off. The barbs would hopefully serve to keep the blade migrating deeper, rather than backing out. Of course, the tradeoff is that you're filling up the wound channel with the blade and it would slow down blood loss via the channel.
I see them as okay for the price. Nice to have something you can carry absolutely anywhere with no worry of magnetic/metal detection.