The drive system is belt driven and results in zero additional backlash.  See the autofocus image.  You will notice that the V-curve is very symmetrical and the "V" is nice and sharp. This means the backlash is very low and any backlash is likely from the EAF itself. 

The side opposite the EAF has a standard Synta shoe/saddle for mounting additional accessories such as an ASIAir or Pegasus Powerbox etc.   

Redcat 51 notes:  The bracket can be mounted with or without the top handle and different length mounting screws are provided.   The design also allows the bracket to remain on the scope even when the dew shield is reversed, covering the rubber grip for transport.

REDCAT 51 VERSION NOTE: There have been 3 versions of the Redcat 51. The original (V1) had two threaded mounting holes on the side of the scope ring. The later two versions (V1x and V2) have 4 threaded holes on the top of the scope ring. This bracket will work with V1x and V2.