Specification: 1. Item name: 3.17mm RC Aluminum Bullet Propeller Adapter Holder 2. Material: Aluminum 3. Color: Black 4. Motor Axle hole diameter: 3.17mm 5. Single item size: 2.4 x 1.2cm 6. Package weight: 25g Package includes: 5Pcs x RipaFire® 3.17mm RC Aluminum Bullet Propeller Adapter Holder Please note:Sold only by RipaFire,RipaFire company never sold these items to other vendors, be careful! Our products have been tested, if any problem, please contact us at the first time so that we can supply the best service for you.