Black & Decker 90543502 Line Trimmer Spool Spring Genuine Original Equipment Manufacturer (OEM) Part This part is compatible with models including; NST1024 TYPE 1 Spool spring 90543502 attaches inside the cutting line spool and holds the inner spool in place Genuine Original Equipment Manufacturer (OEM) part. Compatible Brands: Black & Decker This spool spring (part number 90543502) is for line trimmers Wear work gloves to protect your hands when installing this part