Arundel's Sideloader doesn't need to do everything. It just needs to work great on the seat tube of a smaller or a compact frame. And it does. The Sideloader is really a 3/4 loader, since it's easier to holster the bottle that way. The Sideloader also comes with a longer spine channel with additional mounting holes, in order to fit as many brands and sizes of frames as possible.
When mounted on the bicycle's seat tube, the SideLoader will release bottles to the rider's right. When mounted on the down tube, the SideLoader will release bottles to the rider's left. The OtherSideLoader opens in opposite directions relative to the SideLoader. To mount two bottle cages that open in the same direction, order one of each configuration.
Arundel bottle cages include stainless steel m5 x 15 mounting bolts that require a 4 mm hex wrench for installation.