Use linq to combine 2 classes into a 3rd collection - vb.net

Question

If I have 2 classes and want to take 2 properties from each class, and combine them into a separate collection, how would this be done using linq?
Say the 2 classes are:
class guitars
public ID
public title
public manufacturer
end class
class drums
public ID
public title
public manufacturer
end class
I tried this, but it didn't work:
Private Interface Instruments
Property ID As String
Property name As String
End Interface
Dim results = From item In guitars _
Select New Instruments() With _
{ _
.ID = item.ID, _
.name = item.Title _
}
Dim results2 = From item In drums _
Select New Instruments() With _
{ _
.ID = item.ID, _
.name = item.Title _
}
Dim combined = results + results2

Answer 1

You can make it much simpler than that.
Just make both classes implement the IInstrument interface.
You can then write
guitars.Cast(Of IInstrument)().Concat(drums)

Answer 2

Union or Concat depending on wether or not you want to allow duplicates in the list.
http://msdn.microsoft.com/en-us/library/vstudio/bb763068.aspx
Dim Combined = results.Union(results2) ' no duplicates allowed
Dim Combined = results.Concat(results2) 'duplicates allowed
EDIT: Added Concat at the behest of MatthewWhited. He is totally right. The list is distinct according to the MSDN.