Shown is the FBB16U fuse box clipped to three RB4U standard relay boxes. Two FHA240 single fuse holders are clipped the the right hand end. These could also be upto two RBW1U standard relay holders or one RBB1U heavy duty relay holder. We would recommend clipping no more that one addition item to each of the two holder brackets. Additional holder brackets are provided on the FBB16U fuse holder, RB4U relay holder and RB7U micro relay holder on one side only. There are no brackets on the left hand end of the assembly and once a box is clipped to another, only the last box holder brackets are available as shown in the photograph.