Determine the dimensions and tolerances shown in the technical drawing, including angles, lengths, and radii, and identify any specified surface treatments or finishes.

This is a double-V butt weld (also known as a double-bevel butt weld).

A double-V butt weld is a type of butt joint where both pieces of metal are prepared with a V-groove on both sides of the joint. This allows for welding from both sides, which is often used for thicker materials to ensure full penetration and reduce distortion. The diagram shows a 45-degree bevel on the top side of each plate and a similar preparation on the bottom, with a root opening of $2 \pm 1$.