61802-2RS Sealed Ball Bearing ABEC-5 Quality with Si3N4 Ceramic Balls (Silicon Nitride) 15mm x 24mm x 5mm 61802-2RS is double sealed, radial and deep groove ball bearing,61802-2RS bearing is closed with rubber seals to protect the bearing from dust or any possible contamination,bearings is sealed and self lubricated,the quality is set to EMQ (ABEC-5 quality) to ensure high speed,bearings is lubricated with grease.61802-2RS bearing is made of Chrome Steel with Ceramic Balls (Si3N4) and Chrome steel cage,