I think we are still confused about which is which. The Galazan bore micrometer is very simple and portable, sells for about $129.00 and a near identical item is sold by Brownell's for about $90.00. It goes up the barrel at least 15 inches. The Galazan wall thickness gauge is a $400.00 plus item and sits on a table and does not measure bores. The shortcoming of the Galazan bore micrometer is that it will only measure 10-16 in one size, and 20 and 28 in another. The Louis gauge does all sizes.