Outer diameter: 7mm Length: 13mm Bore diameter: 3mm-3mm、 both ends can connect to 3mm shaft; Support 200 degree rotating. Delicate workmanship、 suitable for all kinds of science model drive、 such as model airplane、 archaizing caique etc. Dimensions: 0.51 in x 0.28 in x 0.28 in (1.3 cm x 0.7 cm x 0.7 cm) Weight: 0.18 oz (5 g)