The GRK Trim head screws have the smallest head on the market and are offered in lengths from 1-5/16" to 5". There are several types of Trim Head Screws available from GRK: The Trim RT Composite™, Trim RT Composite™ Stainless Steel, FIN/Trim™, and the FIN/Trim™ Stainless Steel. The Stainless Steel screws are 305 grade. Pheinox Stainless Steel is GRKﾒs one-of- a-kind stainless. It is hardened and rust free and maintains the quality you have come to expect from GRK products. All GRK stainless steel products come with a limited lifetime warranty against staining and rusting. All can be used for interior and exterior applications; however, exterior applications are best served with the Stainless Steel options. Pilot holes are only needed if the building material manufacturer requires it. These trim head screws are best suited for window and door jambs and composite decking. FIN/Trim is an excellent choice for most fine carpentry applications. GRK modified its innovative FIN/Trim Head Screw to include reverse threading under the head of the fastener and called it the RT Composite Trim™ Head Screw that is ideal for composite decking construction. After extensive testing, GRK has found that the reverse thread on the RT Composite Trim Head Screw helps the screw disappear beneath the surface of the composite material, reducing or eliminating the dimple that sometimes appears when using the FIN/Trim Screw. GRKﾒs RT Composite Trim Head Screws are recommended for most composite decking projects and climates. The reverse thread feature is available in sizes from 2" to 3-1/8". Always check with the manufacturerﾒs literature for installation recommendations. The self-tapping W-Cut thread design prevents most material splitting and the Zip-Tip™ point assists in easy driving. For best results, Trim screws should be driven at half speed. To prolong the life of the #10 bit, do not use an impact driver on the #8 Trim Head screw. Imported.