These are Lever Bearings for the Thunder Tiger Raptor 30 and Raptor 50 Helicopters. FEATURES: Steel construction Silver in color INCLUDES: Two 4x7x2.5mm ball bearings REQUIRES: Installation into helicopter SPECS: Inner Diameter: 4mm Outer Diameter: 7mm Thickness: 2.5mm lmm 10.21.10 ir/jxs