The dimensions that need to be measured on a seal are the ID, OD and the width, or the thickness. The following is a general guideline for measuring some of the most basic seal designs. The following examples are general guidelines and are not all inclusive. Oil Seals Identifying the manufacturer of an oil seal can be difficult, however many manufacturers stamp the dimensions on the seal. The numbers shown on the seal indicate the size. 70 90 10 shows the shaft of 70mm, the bore is 90mm and the width or height is 10mm. Some seals have different sealing lip configurations, such as single or double. O-Rings Two dimensions are also needed for measuring o-rings correctly. The inside diameter and the cross section (thickness) of the o-ring. There are too many sealing types and variations to address all sealing configurations, please call our seal specialists for further assistance.