THTEN DWO1DT995 Replacement Spring Base Compatible with Dewalt DCST970,DCST922,DCST990,DCST920,DCST925,DCST991 Cordless String Trimmer 4 Pack AC052N1 Blades Compatible with Homelite Models:51978 RY30530

Compatible with Homelite Models:51978 RY30530 RY30550 RY30570 30cc String Trimmer

Compatible with Greenworks string trimmer models 21052 21212 and 21272

BST4000 string trimmers

but lightweight

Fit for all ECHO SRM straight shaft trimmers

THTEN DWO1DT995 Replacement Spring Base Compatible with Dewalt DCST970,DCST922,DCST990,DCST920,DCST925,DCST991 Cordless String Trimmer 4 Pack AC052N1 Blades Compatible with Homelite Models:51978 RY30530DWO1DT995 Replacement Spring compatible with Dewalt DCST970. DCST922,DCST990,DCST920,DCST925,DCST991 cordless string trimmers Compatible with Dewalt 20V,40V,60V cordless string trimmers. Includes 3 pack Dewalt DWO1DT995 Replacement Spring and 1 pack Base. Turn off the trimmer before changing, installing, or removing the Trimmer spool head. Trimmer heads spring made of 100% heat treatment premium galvanized steel, rust resistance,strong compression