Review (1/5): DO NOT BUY THESE UNLESS YOU HATE YOUR HAIR.
AWFUL! The metal itself is flimsy and gets bent out of shape when I try to spin the pins into my bun (my hair isn't super thick or curly). The worst part, however, is that the ball tips are GLUED ON CROOKED, leaving gaps between the end of the pin and the ball tips. Between that inescapable hair trap and the jagged bits of glue still left on the pins, these suckers burrow their entire bent-out-of-shape length into your hair (miraculously avoiding any opportunity to actually hold your bun in place) and then tangle themselves up in all the tiny hairs that will hurt the most when you eventually get tired of trying to extracate the hairpin versions of Chinese finger traps from the gnarled bird's nest you once called your hair and just rip the whole mess out by the roots.
Save your money, your patience, your sanity, and your hair and buy LITERALLY anything else. Airplane epoxy would even be better than these.