How to use CHR(34) a a constant

Is it possible to use CHR(34) (a singe quote mark) as a constant? I have tried:

Private Const Units as string = CHR(34)
Private Const Units as string = "
Private Const Units as string = """

None of those worked! FYI I am using CHR(34) as a representation for inches. I would like to make it so if the user prefered metric the only line he would have to change would be the constant line.

Thanx in advance,

Tom