This is a pack of four 8x14x4mm metal shielded flanged "Speed" ball bearings. ProTek R/C "Speed" bearings are high quality steel/chrome bearings designed for the R/C racing enthusiast.
These 8x14x4 metal shielded bearings are the standard bearing for the Team Losi 8ight differential outdrives. Please check the manual that came with your vehicle for the correct size if you are not certain.