3/8-16 X 5-1/2" 馬車螺絲 | 全螺紋 | A307 A級鍍鋅鋼 (75顆/包)

The square neck design really bites into the wood as you tighten them down, so the bolts don't just spin in place. These are perfect for my heavy-duty bench build where I need a solid, non-slip connection. Excellent quality for the price.

The heads sit flush and smooth, and the square neck pulls tight enough that I didn't have to hold a wrench on the back at all. The zinc plating looks clean and even across all 75 pieces, no rust spots or bent threads in the batch I went through.

The square neck grabbed into the wood instantly when I tightened them, so no slipping or spinning with a wrench. The 5-1/2" length worked perfectly for sandwiching two 2x4s and a bracket, and all 75 heads look clean with no stripped plating.