Tactical Precision Manufacturing TPM Titanium Helical Fluted Bolt Knob Polished Titanium 5/16x24. These bolt handles improve the look and increase functionality over factory knob Specifications for Tactical Precision Manufacturing TPM Titanium Helical Fluted Bolt Knob: Manufacturer: Tactical Precision Manufacturing Condition: New Color: Polished Titanium Package Contents: Tactical Precision Manufacturing TPM Titanium Helical Fluted Bolt Knob Tactical Precision Manufacturing BKTI-HF: TPM Titanium Helical Fluted Bolt Knob Polished Titanium 5/16x24