There is a Saddle bag (standard size) and there is a mini size.

Both require a strap that is sold separately, otherwise you have to keep one in hand or have it stuck under your shoulder.

Mini size is really cute, but I don’t see how it can be practical for every day use. It will fit a phone and keys, but not so much more.
I would definitely go for a Saddle bag in a normal size. And I would choose monogram fabric instead of leather, as in my opinion canvas is much more lasting than leather and it is easier to pair with a pair of jeans and a shirt, or some utility style overall (thats how I see it) for a laid back chic.

Dior Saddle in Leather is retailing at 12000 aed in Dubai and Abu Dhabi (in London £2350, in Paris €2500)

Dior Mini Saddle in Leather is 9800 aed (in London £1850 , in Paris €2000).
Prices updated on 28 July 2018.

My work outfit today is Zara Brown Check Blazer and Zara Straight Jeans, Isabel Marant Beth Sneaker.
I made a video for with the size comparison, I hope it will be here in the post, otherwise click here