Excellent quality. Excellent value
This spring is made to the original M16 rifle size specification and is not of the newer "heavy coil" XP-designs. However, these are Chrome Silicon steel, which is perfect for use in the hgih temp, high stress bolt assembly. Regular spring steel can have its temper/strength affected as low as a few hundred degrees Fahrenheit. CS steel can maintain its strength up to ~800 degrees with no damage to its temper. This spring will also outlast your original extractor spring by an order of magnitude. Use this spring with a mil-spec viton O-ring and a black spring insert for maximum life and reliability. You can also use a Defender D-ring instead of the O-ring. If used with the insert and the O-ring, this spring can be used to the same effect as the newer "XP" extractor springs. This spring is a great value. An even greater value in the 3-pack. I hand these out as Christmas gifts to friends. Nothing says "Merry Christmas" like "I hope you stay alive in a gunfight." ;)

