... RC helicopter repair kit makes the perfect gift for any helicopter enthusiast, All sizes and IADC codes ... old one. It also acts as a stabilizer for drill bit. We can produce reaming shells with ... appropriate inner tube extension in order to compensate for the difference in overall reaming shell length. ... "Q" Series: AQ, BQ, NQ, HQ, PQ (Front end & Back end Type) T Series: T36, T46, T56, T66, T76, ...