There are several different types of 688 open Deep groove ball bearings, but they are all essentially the same. Each has an inner diameter of eight millimeters, an outer diameter of sixteen millimeters, and a width of five millimeters. Their primary difference is the cage. The most common type of 688 open Deep groove ball bearing has a riveted steel cage, which is guided by an inner ring. Both cage and seal help maintain lubricant and contaminants out of the bearing.

The MC3 normal clearance of these bearings is referred to as the mounted radial internal clearance, or RIC. The MC3 normal clearance is the same for standard miniature and extra-small deep groove ball bearings, but the MC3 is different for these types. The MC3 clearance is the same as the MC3 clearance for deep groove ball (and other) bearings. Listed below are the available RICs for standard, miniature, and extra-small deep groove ball-bearings.

The 688 series miniature deep groove ball bearings are a popular choice for small, thin shafts. The narrow bore allows for installation in a tight space and high speeds, and they are easy to mount and require less maintenance than other types. The SS-F-688-W4 is a stainless steel miniature deep groove ball bearing that is suited for extreme environments. Among the most common uses for these types of bearings, the SS-F-688-W4 features a metric special dimension, is corrosion-resistant, and is ideal for applications requiring low- or no-maintenance.

The ISO 281:2007 procedure is used for the published dynamic load ratings of 688 open Deep groove ball bearings. The dynamic load rating is defined as the radial load under which a population of identical bearings can achieve L10 life of one million revolutions. It is assumed that the radial load is constant in magnitude and direction. If the bearings are designed for a specific application, the radial load is specified as a constant.

The 600 type is a miniature deep groove ball bearing. Its size is very small and is a popular choice for high-speed, low-noise applications. They are available in many sizes, including large and complex models. The XUANYE Precision Machinery Co., Ltd., founded in 2006, is a large manufacturer of miniature deep groove ball bearings. Their manufacturing facility covers approximately 88,850 square meters and employs 500 people.

Despite the wide range of 688 ball bearings, they are still the most common of all rolling bearings. Their high-speed performance and relatively low price have made them popular in a variety of applications. These small, open ball bearings are also great for factory automation and rotary machines. The six-inch 688 is one of the most commonly used types of miniature ball bearings. The 8-mm version of this model has an inner diameter of eight millimeters and an outer diameter of sixteen millimeters and a width of four millimeters. They are a popular choice for a variety of rotary and axial motions.