Required rear weight box for counter balance when using HL900 Loader without a backhoe or without a RH65 Three Point Rear Hitch with any 750 lb tractor attachment. Comes with both rigid tractor mount (shown in the picture) and with bracket to connect to the RH65 Three Point Hitch. FB150 Weight Box not required if HL900 Loader and D1065 or D108 Backhoe are mounted simultaneously.