Jorgensen 104 C-Clamp 4" Metric while the smooth side is

while the smooth side is ideal for polished stainless steel

For posts measuring 3-1/2" x 3-1/2"

so they can't come inside

=1-1/2 x 16

M3 steel provides longer life then the MS steel of the industry standard product

Jorgensen 104 C-Clamp 4" Metric while the smooth side isMost universally used general purpose "C" clamps for regular duty industrial service. Frames are liberally proportioned and heat treated for maximum strength. Longer frame hubs and special, square thread screws assure durability. Highlights: The most universally used class of "C'" CLAMP Liberally proportioned frames, specially treated for greatest possible strength Cold drawn steel screws of more than adequate diameters, carefully fitted Vise type