One piece, 4.4 grams, which is lighter than most top caps without the screw. Fair warning, being one piece and aluminum, it is NOT going to stand up to hamfisted mechanics.Addressing the other reviews - complaining about a Torx that you stripped out - Torx is more resistant to stripping, if you had a hex you'd have stripped that sooner. To the person who stripped it using a torque wrench - you don't use a torque wrench with top caps, you just apply enough tension to remove the play in the headset, and then you torque the stem bolts to hold that setting.So yes, if you're hamfisted and don't know how to use topcaps, this probably isn't for you. If you're a weight weenie that knows how to adjust a headset, this might just work for you.