Co-Ax Indicator Milling Machine Coaxial Coax .0005'' Axis Straight Curved Feeler Accuracy to Within .0002" of True Center; .0005" Graduation ; 6-7/8 Length ; 3/8" Diameter x 7/8" Long Shank 1/8" Diameter Feeler Ball ; 250 Axis Offset Measuring Range ; 5/32 to 4-1/4 Diameter Internal Capacity ; Zero to 4-1/4 Diameter External Capacity ; It is Recommended that the Operating Speed not Exceed 800 RPM Approximately ; All Points Included - Great for set ups in Mill ; Designed for Centering a Work Piece of Fixture ; Operates at Any Angle ; Use Vertical or Horizontal ; User Internal or External ; While Spindle Rotates, the Centering Indicator Always Faces the Operator 6 Points and Feeler Included ;Restraining Rod Center Point Feeler;Case overall dimension: 4-3/4''L x 8-5/8''W x 2-1/2''H; Quantity: 1; Weight: 1.55 lbs 2" Straight Feeler 4" Straight Feeler 6" Straight Feeler 2" Curved Feeler 4" Curved Feeler 6" Curved Feeler