There are many different places to get harnesses online.

The type of harness you order depends on the type of cart and attachment options that your cart has.

Nordykn Outfitters make many different types of harnesses and specialize in the siwash style.

Howling Dog also has a variety of harnesses. Most of their harnesses are used by sledding enthusiasts. They have a marvelous Pulka style harness that works very well with dual shaft dog carts.