Based on extensive tests, GRK has found that the reverse thread helps the screw head disappear beneath the surface of the classic wood composite material, reducing or eliminating the dimple that sometimes appears when using the FIN/Trim™ screw. The reverse thread feature is available in RT Composite™ screws from 2” to 3-1/8” in length in both regular Climatek™ coating and in white Climatek™ coated finish to blend in with popular white exterior composite and cellular PVC trim. https://youtu.be/Egx8Ik2dfCE