ECHO & SHINDAIWA THUMBSCREW Echo & Shindaiwa Genuine OEM Part Original Factory Package & Label Echo & Shindaiwa Genuine Part A235000201 is used on models CS-550P 54.1cc Chainsaw-CS-600P 59.8cc Chainsaw-CS-550P (C10712001001 - C10712999999) 54.1cc Power Boost Engine Chain Saw-CS-550P (C14113001001 - C14113999999) 54.1cc Power Boost Engine Chain Saw-CS-590 (C25812001001 - C25812999999) 59.8cc Timber Wolf Chain Saw-CS-590 (C25913001001 - C25913999999) 59.8cc Timber Wolf Chain Saw-CS-600P (C03603001001 - C03603999999) 59.8cc Professional Cutting System Chain Saw-CS-600P (C03704001001 - C03704999999) 59.8cc Professional Cutting System Chain Saw-CS-600P (C22312001001 - C22312999999) 59.8cc Professional Cutting System Chain Saw-CS-600P (C22413001001 - C22413999999) 59.8cc Professional Cutting System Chain Saw-CS-620P (C26712001001 - C26712999999) 59.8cc Professional Grade 2-Stroke Engine-CS-620P (C26813001001 - C26813999999) 59.8cc Professional Grade 2-Stroke Engine-CS-620PW (C26912001001 - C26912999999) 59.8cc Professional Grade 2-Stroke Engine-CS-620PW (C27013001001 - C27013999999) 59.8cc Professional Grade 2-Stroke Engine