TYPES: #extent-1 materialExtent, CreativeWork

PRE-MARKUP:
<div>
  Name: Assorted collection of items<br/>
  Extent: 285 A boxes, 8 OS boxes (plus 45 T boxes, 50 A boxes, 13 OS boxes / items uncatalogued)<br/>
</div>

MICRODATA:

<div itemscope itemtype="http://schema.org/CreativeWork">
  <link itemprop="additionalType" href="http://schema.org/ArchiveComponent"/>
  Name: <span itemprop="name">Assorted collection of items</span><br/>
  Extent: <span itemprop="materialExtent">285 A boxes, 8 OS boxes (plus 45 T boxes, 50 A boxes, 13 OS boxes / items uncatalogued)</span><br/>
</div>

RDFA:

<div  vocab="http://schema.org/" type="CreativeWork ArchiveComponent">
  Name: <span property="name">Assorted collection of items</span><br/>
  Extent: <span property="materialExtent">285 A boxes, 8 OS boxes (plus 45 T boxes, 50 A boxes, 13 OS boxes / items uncatalogued)</span><br/>
</div>

JSON:

<script type="application/ld+json">
{
  "@context": "http://schema.org",
  "@type": ["CreativeWork","ArchiveComponent"],
  "name": "Assorted collection of items",
  "materialExtent": "285 A boxes, 8 OS boxes (plus 45 T boxes, 50 A boxes, 13 OS boxes / items uncatalogued)"
}
</script>

TYPES: #extent-2 materialExtent, CreativeWork

PRE-MARKUP:
<div>
  Name: Assorted collection of items<br/>
  Extent: 1 folder containing 5 design drawings<br/>
</div>

MICRODATA:

<div itemscope itemtype="http://schema.org/CreativeWork">
  <link itemprop="additionalType" href="http://schema.org/ArchiveComponent"/>
  Name: <span itemprop="name">Assorted collection of items</span><br/>
  Extent: <div>
            <div itemprop="materialExtent" itemscope itemtype="http://schema.org/QuantitativeValue">
              <span itemprop="value">1</span> <span itemprop="unitText">folder</span>
			</div>  
			containing 
            <div itemprop="materialExtent" itemscope itemtype="http://schema.org/QuantitativeValue">
              <span itemprop="value">5</span> <span itemprop="unitText">design drawings</span>
			</div>  
          </div><br/>
</div>

RDFA:

<div vocab="http://schema.org/" type="CreativeWork ArchiveComponent">
  Name: <span property="name">Assorted collection of items</span><br/>
  Extent: <div>
             <div property="materialExtent" type="QuantitativeValue">
              <span property="value">1</span> <span property="unitText">folder</span>
			 </div>
			 containing 
             <div property="materialExtent" type="QuantitativeValue">
              <span property="value">5</span> <span property="unitText">design drawings</span>
			 </div>  
          </div><br/>
</div>

JSON:

<script type="application/ld+json">
{
  "@context": "http://schema.org",
  "@type": ["CreativeWork","ArchiveComponent"],
  "materialExtent": [
          {
            "@type": "QuantitativeValue",
            "unitText": "folder",
            "value": "1"
          },
          {
            "@type": "QuantitativeValue",
            "unitText": "design drawings",
            "value": "5"
          }
       ]
}
</script>