{% if connection_type == "iso_thread" %}
<label>ISO Thread
  <select name="iso_thread_id" required>
    <option value="">— select —</option>
    {% for t in iso_threads %}
      <option value="{{ t.id }}"
        {% if ap and ap.iso_thread_id == t.id %}selected{% endif %}>
        M{{ t.diameter_mm }}×{{ t.pitch_mm }}{% if t.depth_mm %} ({{ t.depth_mm }} mm deep){% endif %}
      </option>
    {% endfor %}
  </select>
</label>
{% elif connection_type == "unc_thread" %}
<label>UNC Thread
  <select name="unc_thread_id" required>
    <option value="">— select —</option>
    {% for t in unc_threads %}
      <option value="{{ t.id }}"
        {% if ap and ap.unc_thread_id == t.id %}selected{% endif %}>
        {{ t.diameter_fraction }}-{{ t.tpi }} {{ t.series.value }}{% if t.depth_in %} ({{ t.depth_in }} in deep){% endif %}
      </option>
    {% endfor %}
  </select>
</label>
{% elif connection_type == "clamp_connection" %}
<label>Clamp Connection
  <select name="clamp_connection_id" required>
    <option value="">— select —</option>
    {% for c in clamp_connections %}
      <option value="{{ c.id }}"
        {% if ap and ap.clamp_connection_id == c.id %}selected{% endif %}>
        #{{ c.id }}
        {% if c.min_mm is not none %} {{ c.min_mm }}–{{ c.max_mm }} mm{% endif %}
        {% if c.min_in is not none %} / {{ c.min_in }}–{{ c.max_in }} in{% endif %}
      </option>
    {% endfor %}
  </select>
</label>
{% elif connection_type == "static_connection" %}
<label>Static Connection
  <select name="static_connection_id" required>
    <option value="">— select —</option>
    {% for s in static_connections %}
      <option value="{{ s.id }}"
        {% if ap and ap.static_connection_id == s.id %}selected{% endif %}>
        {{ s.od_mm }} mm / {{ s.od_in }} in OD
      </option>
    {% endfor %}
  </select>
</label>
{% endif %}