The AXJ Encoders allow you to greatly advance tracking performance of the AXJ equatorial mount.
Generally computerized equatorial mounts have automatic "Go-to" system which is designed to have a position of the equatorial mount indicated on the controller correspond with a direction of the telescope. If you unfasten the clamp levers on the equatorial mount while using the automatic "Go-to" system, the telescope will lose information on identifying the positions and the "Go-to" will be useless. So, it was unable to move the telescope manually. With use of the AXJ encoders, lt allows the AXJ equatorial mount to keep always having the position of the equatorial mount indicated on the controller correspond with the direction of the telescope. You will be able to enjoy "Go-to" slewing with easier as you can loose the clamp levers and change the direction of the optical tube by hand.
The AXJ encoders watch the tracking motion of the AXJ equatorial mount in the resolution of 0.1 arc second (R.A.) for a level higher accuracy. Subtle periodic errors can be detected for corrections and the tracking of extremely high precision is a result. (Periodic error < 0.5 arc seconds rms typically at sidereal tracking with the AXJ mount.)
The AXJ encoders will be installed neatly on the inside of the equatorial mount body without affecting the looks. So, it is not necessary to care the size of a storage case.