These Circular Tree Clips, also known as "ratchet fasteners," are non-removable. Flexible ribs on the shank bend when the X-mas tree type fasteners are pressed into a hole then snap back inside the hole for a secure fit. This provides equal tightness anywhere along the clip shank, and makes these nylon barbed rivets ideal for applications of variable panel thicknesses. Available in a broad assortment of styles that give designers great leeway, Circular Tree Clips are offered in a wide range of panel thicknesses and hole sizes.