Check the listing for details. David Brown Precision Adjustable Boring head SET 3. Condition: Used. Listed at 299.95 USD. The David Brown Precision Adjustable Boring head is a high-quality toolholding accessory designed for CNC machining and metalworking applications. With precise adjustable capabilities, this boring head ensures accurate and reliable results for boring and drilling operations. Ideal for professionals in manufacturing industries, this product helps to improve efficiency and productivity by providing a secure and stable grip for various cutting tools.