With the OP/TECH USA System Connectors, you have several connection options. All of the OPTECH straps with clips that connect the shoulder pad to the strap ends are interchangeable. The beauty of this is being able to use any shoulder pad with any camera strap, bag strap, etc. You can save yourself some money on straps by having a couple pads and several strap ends attached to the equipment so you can connect and go. The strap ends also clip together making a short strap of their own so you have that option as well. Personally I leave the shoulder pad off the camera around the house for snap shots so I can just grab the short strap and go.
System Connector Available 
1 = Swivel Hooks
2 = Adjustable
3 = 3/8" (9,525mm)
4 = Pro Loop
5 = Super Pro A
6 = Super Pro B
The number next to the strap is the reference for the list above.
This listing is for a brand new pair of the Pro Loop connection ends. The list above is just for reference to inform you of your other options.
The Pro Loop strap is one of those generic type connection ends. I like the Loop ends because they are flexible and drop easily out of the way when raising the camera up to shoot. They will attach to almost anything that uses a strap, cameras, binoculars, scopes, a rifle, camera bag, etc. The most popular new Digital cameras like the Nikon D70, Canon 10D or 20D are both professional grade cameras that benefit from a nice OPTECH strap. The professionals I know also use these on their long and fast telephoto lenses. If you have one you understand they can be a burden to carry around but you can't leave it sitting somewhere. These will attach right to the lens and you can select the suitable shoulder pad to go with it. Most go with the Super Classic and get extra ends like this to attach to all their lenses and buy the minimum complete straps to have enough for carrying what's needed.
