Spring lock washers STL,20MM,21 MM ID,4 MM TH,#0 DESIGN CONFIGURATION: HELICAL SPRING; NOMINAL SIZE: 20 MM; INSIDE DIAMETER: 21 MM; OUTSIDE DIAMETER: 32.6 MM; THICKNESS: 4 MM; MATERIAL: STL; STANDARD/SPECIFICATION: NAVISTAR® ESP FM-1.101-GS; ADDITIONAL DATA: HELICAL SPRING,REGULAR TYPE. UNIDENTIFIED MANUFACTURER - SOA: P/N#0 311.012 QTY : 40