MailItem.ConversationIndex max length

Hi,

I need to store this in a SQL database. What is the best datatype / length to use in both SQL and ADO:

Code:

---


ADO:

.Parameters.Append .CreateParameter("@BatchId", adVarWChar | adLongVarWChar, adParamInput, XXXXX, BatchId)

SQL:

nvarchar(YYYYY)

---

Thanks