Replacement front collison/lift sensor. Used on 310, 315, 315X, 430X, 430XH, 450X, 450XH, 520, 520H, 550, 550H, 450X EPOS, 450XH EPOS, 550EPOS, & 550H EPOS models of Husqvarna Automowers. 
 
Video: Lift and collison sensor system explained