BORING ADAPTORS (not included): -End stop for different boring depths. -Suitable for any type of drilling machine. -Duralumin body with holes for better chip ejection. -Precise and flat seating for proper alignment. CMT400-1: Boring adaptor for CMT656, CMT900 jigs to be used with drill bits up to 30mm in depth: 306.030.21 – 306.050.11 – 306.080.11. CMT400-2 (for screw joints): Boring adaptor for CMT656, CMT900 jigs to be used with drill bits from 30mm to 40mm in depth: 307.050.11.