All copper, great price
Surprisingly, these are not copper-plated. They are solid copper. I clipped a pin to check. That alone makes them the best value i can find here or on newegg in the small heat-sinks category.I only needed 4 of 8, so decided to deploy them on various southbridge chips to good effect.The pre-installed stickers make good thermal contact, and they solved my heat problems. They might not have been enough for video card ram, but they were more than enough for some very toasty little (allegro) motor drivers ('ow, burned myself' 90 c toasty became 44 c 'not even that warm').My only complaint is that in my experience they don't stick particularly well: i brushed one off accidentally.  1 of 4 dropped off after ~6month high-vibration operation.That might be fixed with thermal compound, epoxy, and/or unmolested operation with favorable conditions. note: i cleaned contact surfaces with alcohol wipes (clean is important; you get one shot).Very effective and versatile, my only knock against them might be spurious if applied properly.