3M 92765, Between Coats Finishing Pads, Open Stock 10144NA, 3-3/4 in x 6 in x 5/16 in, 7000122788 
Insize 4168-8E, STEEL STANDARD BALLS, 5/16″, 6940561981469
$13.52
To measure angle and diameter of taper holes
Material: tool steel
Hardness: HRC63
Diameter accuracy:?.00012?
Roundness .00004″
Supplied with manufacturer inspection certificate.
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