#2137 KUBOTA U25 ZAPII 2.2 Ton MINI Excavator [3.9 hrs] with Expandable tracks [MACHKUBO]
#2190 KUBOTA U55 [5.5Ton] Steel Tracks Compact Excavator [ONLY 5.4 HOURS] [MACHEXC]
#2148 KUBOTA U57 5.5 Ton KX-57 Excavator [7.2 hours] KX57 Steel Tracks with Rubber pads [MACHEXC]
#2141B KUBOTA U35 ZAPII 3.2 Ton Excavator [4 hrs] [MACHKUBO]
#2204 KUBOTA U55 5.5 Ton Rubber Tracks Compact Excavator [6.3 HOURS] [MACHEXC]
The item you are attemping to add to compare is a different subtype to the items(s) in your list.
Only items of the same subtype may be compared.