5 pack of World Champion ACER Racing 5x10x4mm Ball Bearings.  5x10mm ball bearings also known as size MR105 ball bearings and TAMIYA 1050 bearings

Direct replacement for Tamiya TRF 42113

HSR cage technology and sealed on both sides.  Super fast and super smooth action. Price is for five 5x10x4mm ball bearings as shown in the photo.