New Popular Locking Nut and String Retainer - Black M05906 Locking Nut and String Retainer - Black Locking Nut and String Retainer - Black $50.00 SKU: M05906 Quantity − + Add to Cart In stock Ready to order from our store. Notify me when in stock Email address for a restock alert Notify me We'll email you once, when this is back — that's it. No newsletter, and your address is only used for this alert. Privacy policy. Save to wishlist Ships from California. Free ground shipping on orders of $100 or more.