SKF internal clearance gauges in the GB 30 and GB 10 series are designed for use with double row cylindrical roller bearings ranging from NN 3006 K to NN 3068 K (GB 30 gauges) and for use with single row cylindrical roller bearings ranging from N 1010 K to NN 1020 K (GB 10 gauges). In general, gauges in the GB 30 series can also be used for single row bearings in the N 10 K series. GB 30 and GB 10 internal clearance gauges are able to accurately measure the outside envelope diameter of the roller set when the rollers are in contact with the inner ring raceway.

Depending on their size, GB 30 and GB 10 internal clearance gauges consist of either a two piece or a slotted gauge body that holds two diametrically opposed ground gauging zones († fig. 4). The gauge body can be expanded by means of an adjustment screw. This enables the gauge to be pushed over the inner ring with roller and cage assembly, without damaging the rollers or the gauging zones. The gauging zone that is connected to one half of the gauge body transmits the diameter measured by both gauging zones to a dial indicator.