I tried these when I got my mini tweed rectangular. I bought them from
Amazon and I liked how they came in varying hardware colors. However, I like to be able to vary the strap length; sometimes I like to wear the bag on my shoulder, sometimes I like to carry it in my hands and sometimes I like to wear it crossbody with a bulky coat, etc, so I removed the shortening clip because it has to be screwed into place with a mini screwdriver and you cannot change it easily while on the go... Now, I use a small safety pin or I loop the chain around itself. Also, I did accidentally scratch the leather interior while using the screwdriver

They are a good option though if you know the length that you want and you only want to wear the bag one way.