5/16-18 × 3-1/2" براغي آلية | رأس مسطح بمحرك مشقوق | فولاذ مقاوم للصدأ 18/8 (100 / عبوة)

Had to swap out some old screws on a pergola that gets blasted by rain all year, and these 304 stainless ones slid right in without any binding. The 3-1/2 inch length grabbed perfectly through pressure-treated lumber, and the flat head sits flush so nothing snags.

Used these for a boat dock repair and the 18/8 stainless is holding up perfectly against the saltwater spray. The slotted heads let me really torque them down without stripping.

Installing these in a stainless steel railing project and the 18/8 material feels solid, should hold up well outdoors. The 3-1/2 inch length was exactly what I needed to get through the wood and into the framing.