Not to be confused with the SP-1 model. This Carrier is manufactured to work with a registered “Lightning Link”. see our explanation of the two types of carriers under “Frequently Asked Questions”. Available in chrome or phosphate finish. Please Specify.What makes Young Manufacturing AR15 bolts and bolt carriers so accurate? Find out more about our precision bolts and AR15 and M16 bolt carriers and see our “What makes our Bolt Carriers Better?” on our home page.