The Ideal® Round 170R has a plate size of 0.6825" (17mm) diameter, which provides an impression area of slightly less than that--about 1/16" less.
This is a great stamp to use for inspectors when only a number or initials are required. Also good for small logos. Designed for professional inspection marking on porous surfaces. No separate stamp pad needed, simple to re-ink. Compact, ideal and convenient, fits 
easily in an inspector's pocket for use when needed. Click on Photo Image for an Enlarged Picture.
Just one impression and you’ll appreciate the heavy-duty construction, ergonomic design, and patented precision components used to create a smooth, quiet stamping experience. Make thousands of impressions with Ideal stamp ink that is formulated for clean, crisp, fast drying impressions without bleeding or fading on most paper stocks. Accurate re-inking of the Ideal 170 Round Inspector Stamp is a snap with the Ideal re-inking system.
Ideal self-inking stamps are the biggest selling brand of self-inking rubber stamps in America, and are perfect for home and business use.