Zenith Archery Products Bitzenburger Upgrade Kit Zenith Archery Products has introduced a new upgraded nock receiver for your Bitzenburger fletching jig. The replacement body will fit directly into your jig and will still adjust for all three different fletching patterns. The original receiver held the arrow only by a loose fit on the nock. The new receiver comes with two inserts which are held into the body by a long screw which is tightened through the rear of the receiver and will hold the arrows directly, without slippage. One insert is sized to fit snuggly into any arrow which uses a G nock. The second insert does arrows which use pin nocks, holding the pin by the hole in the insert. It also does arrows which use Super nocks (.246 carbon, Super Uni-bushings, etc.) by fitting the insert into the back of the arrow. If the pin holder becomes too loose, just gently squeeze the segments together with a small plier until it holds the pin tightly again. This kit DOES NOT include a sleeve for X or H nocks. These are available as an option if needed. An adjustable upper support plate is mounted using the template and hardware included with the kit. Once the arrow is mounted in the jig, the plate is adjusted to support the upper end of the shaft. Older arrows with glue on nocks can still be done using the old receiver. This will not work with crossbow bolts. There was a change in design by bitzenburger around 25 years ago and this may not work with jigs older then that.