The adjustment knob of C2 grinder has been upgraded to metal material. Timemore replaces the spring inside the burr group. This spring replacement has no effect on grinding efficiency and consistency of coffee powder thickness. The biggest difference between C3 and C2manual grinder is that C3 has been upgrad-ed with new burr. The newly designed 38mm S2C 660 burr isapplied to C3 manual grinder. Better grinding quality and more uniformparticle consistency enable us to obtainbetter coffee flavor cleanliness, rich andbalanced quality and strong body. If you are looking for a cost-effective andprofessional grinder, C3 will be your priority. Rotate clocewise for Finer grinding. Rotate anti-clocewise for coarser grinding. Rotate clockwise to the end, this position is called START POINT. You can refer to the start point to adjust the Coarseness which you prefer. Product Name :Timemore Chestnut C2 Coffee Grinder Size:Body147mm x52mm, Handle 159mm Weghit: 430g Colour:White/Black/Red/Blue. Or, you can choose to get a replacement. Our goal is to ensure a happy shopping experience with us.