Geberit Duofix M12 Threaded Rod Set, which is a pair of bolts used for fixing wall-mounted toilets and bidets to a compatible Geberit Duofix installation frame. 
Key Details and Compatibility
Product Type: A set of two M12 threaded rods with accompanying bolts and protective covers.
Dimensions: The rods are 175mm in length.
Compatibility: They are designed for use with various Geberit Duofix frames for wall-hung WCs and bidets, including models such as 111.335.00.5, 111.335.00.6, and 111.728.00.1. They also fit the Geberit Kappa 15 (UP200) frame and certain AquaClean models.
Function: These rods provide the essential structural support, securely mounting the toilet or bidet pan to the hidden frame within the wall.