Range 3mm to 13mm (1/8" to 1/2") Ideal for measuring slots, holes, grooves and recesses. The satin finished knurled handle allows fine adjustment of the gauge within the workpiece. The split ball contacts are hardened for greater accuracy and longer tool life. Use in conjunction with a micrometer to accurately measure internal dimensions. Supplied in plastic storage wallet. Contents: Size A: 3 to 5mm (1/8" to 13/64") - 90mm overall length, Size B: 5 to 7.5mm (13/64" to 19/64") - 99mm overall length, Size C: 7.5 to 10mm (19/64" to 25/64") - 110mm overall length Size D: 10 to 13mm (25/64" to 1/2") - 110mm overall length. For holes, slots and recesses beyond the range of the small hole gauges use Kennedy Telescopic Gauges.