Features: Replacement bar nuts help maintain saws so they can continue to provide the best performance while cutting and trimming. Made for durability and long lasting use. These bar nuts are comparable to OEM 503220001 bar nuts. They are 8mm- x 1.25 thread 13mm- hex- nut size with a flanged side for proper retention. They can be used with compatible chainsaw- blades-. This package comes with the perfect amount of replacement nuts. Keep them on hand in a tool box or chainsaw- for case for those times when you encounter a lost, damaged or loose nut. These nuts screw on easily with a scrench tool. Remove bar nuts, if needed. Use a bolt wrench or scrench for chainsaw- to tighten the bar nuts securely. Be careful not to strip nuts. for models- like: MS170 MS180 MS230 MS250 MS260 MS290 MS360 MS390 MS380 MS381 MS440 MS460 MS640 MS650 MS660 009 010 012 015 020T 021 023 025 024 026 028 038 031 032 034 036 041 042 044 046 048 050 051 056 064 066. Specifications: Material: stainless steel Quantity: 30 pc/set Package Includes: 30x Bar Nuts note: Please allow 1-3cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item.