Rivet Nut Headstyles

FLAT HEAD presents the largest bearing area against the parent material and is the most commonly used. The head can be used as a spacer to separate the assembled parts, or the space eliminated by boring to allow the head to sit below the surface.
 

LOW PROFILE, also referred to as REDUCED HEAD. This headstyle replaces the need to countersink the parent material and reduces the gap between the materials. If no gap is required, a shallow countersink could be made. It is not recommended to use this type if the joint is under extreme tension or the parent material is soft, which could cause the small head to pull through.

From the outside, the difference between the low profile head nutsert on the left is clearly illustrated against a flat head nutsert shown on the right.