The unique shape of the triangle ring makes them preferable to D-rings for attaching straps to bags.  The design prevents twisting when the strap is under load. 

Set of two.

We do our best to give you an idea of what skill level is needed to make each bag pattern we carry. Here is what we have in mind with each rating:

• Beginner - You've never made a bag before. You have basic sewing knowledge. Projects are usually small and flat.
• Intermediate - You've made smaller projects with basic features and are ready to try something a little more difficult. Projects are medium sized and have a little, basic dimension.
• Intermediate-Advanced - You've had a chance to try more advanced features like recessed zippers, gusseted pockets, and shaped bags. Projects are large and have a lot of dimension and binding.
• Advanced - You've made large projects, and at this point, nothing about bag making is foreign to you. Projects are usually larger and have a lot of shaping, dimension and binding.