2 pack, 40a, 250v, indicating fuse, fusetron dual element, time delay, current limiting class rk5 fuse, label darkens if fuse has opened, applications, ac power distribution system mains, feeders & branch circuits, motors & motor branch circuits, transformers & other inductive loads, lighting, heating & other non-inductive loads, ul listed, dimensions: 2.375"l x 1.375"w x 0.25"h.