Name	Description
cdrom
com
disk
media
optical
printer
processor
raid
scanner
tape
unknown
worm

         <simpleType xmlns="http://www.w3.org/2001/XMLSchema" xmlns:vim25="urn:vim25" name="VirtualMachineScsiPassthroughType">
            <restriction base="xsd:string">
               <enumeration value="disk"/>
               <enumeration value="tape"/>
               <enumeration value="printer"/>
               <enumeration value="processor"/>
               <enumeration value="worm"/>
               <enumeration value="cdrom"/>
               <enumeration value="scanner"/>
               <enumeration value="optical"/>
               <enumeration value="media"/>
               <enumeration value="com"/>
               <enumeration value="raid"/>
               <enumeration value="unknown"/>
            </restriction>
         </simpleType>

Enum - VirtualMachineScsiPassthroughType(vim.vm.ScsiPassthroughInfo.ScsiClass)

Enum Description