b2boptic → items → item → pair → frame

values	description
METAL	metal frame
PLASTIC	plastic frame
OPTYL	optyl frame
NYLOR	nylor frame
DRILLED	frame with drilled holes
SPECIAL	all other frame types
ORGANICMATERIALS	Natural materials (wood, buffalo horn, …)
TITAN	titan frame

<xs:simpleType name="FrameMaterials">
  <xs:restriction base="xs:string">
    <xs:enumeration value="METAL" />
    <xs:enumeration value="PLASTIC" />
    <xs:enumeration value="OPTYL" />
    <xs:enumeration value="NYLOR" />
    <xs:enumeration value="DRILLED" />
    <xs:enumeration value="SPECIAL" />
    <xs:enumeration value="ORGANICMATERIALS"/>
    <xs:enumeration value="TITAN"/>
  </xs:restriction>
</xs:simpleType>