Here's a box of 25,  #10 x 2 1/2"  stainless steel, flat head, square drive  deck screws, Thanks for looking. Deck screws for composite material have curved necks that sink into material to sit flush with the surface. They have sharp points and narrow bodies to penetrate plastic-wood composite decking materials. Steel and alloy steel materials are available with corrosion-resistant finishes for use in outdoor environments.