SideLoader / OtherSideLoader cages solve the problem of cramped space on Compact style road frames, as well as MTB applications. They’re dedicated right or left (fitment specific). One Sideloader plus one OtherSideloader outfits a standard road frame. The shape matches Dave-O’s perfectly.
SideLoaders are for seat tube mount, right side entry; Other SideLoaders are for down tube mount, right side entry. Swap them with each other if you're a lefty… or want the extra clearance of non-drive side access.