Package Include4 Pieces Bicycle Front wheel Bearing 3 or 16" ball size x 7 balls. One pair of wheel bearings for replacements, another for spare. Bearing Size:OUTSIDE DIAMETER: 0.8 inch or 20.5mm, INSIDE DIAMETER: 0.5 inch or 13mm, BALL SIZE: 3 or 16 inch x 7 balls.Please confirm the size before purchase! Application:: This kind of ball bearing stainless steel ball inlaid in the retainer design,It is a bicycle parts, it's suitable for replacing the front wheel's bearing of the bicycle. Widely usage: This beads rack for bike parts replacement, suitable for ordinary bicycles, mountain bikes, mongose bicycle, lowrider bike, stretch bicycle, kids bike. Note: If you receive a 6-ball bearing retainer, they are the same product, have the same size and use. It does not affect the use of.Because they are updating iterative relationships. Item Feature: This ball bearing retainer with 7 balls, which suitable for 16-19mm inner diameter bicycle front wheel axle.It is an ideal replacement for your bike. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.