The Mitutoyo 1909SB-62 Compact One Revolution Type Series 1 Dial Indicator is for error-free reading. Features a unique Shock proof mechanism providing improved immunity to shock due to sudden spindle retraction caused by high impact. Shows the entire spindle travel or range as one sweep of the hand, eliminating the possibility of reading errors due to miscounting the multiple revolutions. With one-revolution dial indicators, "within tolerance" and "out-of tolerance" can never misinterpreted. This model has a Flat Back with a range of .04" and .055" full stroke, .0005" graduation and 20-0-20 Dial Reading with a 3/8" Stem.