Mitutoyo Depth Base Attachment for Mitutoyo Calipers This is an optional accessory to help you more accurately perform depth measurements with a Mitutoyo Caliper. The Depth Base Attachment has a finely ground surface and includes a secure locking clamp. Available in 3" or 4" widths, these Depth Base Attachments will work with the following Mitutoyo Calipers... Mitutoyo 4", 6" & 8" Dial & Digital Calipers Mitutoyo 4", 6" & 8" Vernier Calipers Mitutoyo 100mm, 150mm & 200mm Dial & Vernier Calipers Please select Base Width from pull down menu.