It is designed to allow Canon EF-mount series lens to be used on M43 camera(Autofocus only supports taking pictures, not video recording) 
 More durable metal material, Gold-plated electronic contact, Auto-focus function 
 It can realize AF,adjustable aperture from camera body to lens's aperture 
 Focal length is multiplied by 0.71 based on the original (equivalent focal length =focal length x 0.71), which helps enlarge 1 level aperture.(can not used on F1.2 lens) 
 with 1/4 screws hole, which can easy installed on the tripod or other fixed bracket.