Shoulder eye bolts are very similar in form and function to a regular eye bolt, but they have one added feature — the shoulder (also called the collar). The shoulder allows for the eye bolt to sit flush against the material once it's installed. This really helps in the event of an angular load being applied because it provides greater stability. In fact, the extra strength provided by the shoulder is the only reason an angular load is allowed. Regular eye bolts can only be used in straight-line