Subject: [Mutual Connection] mentioned you
Hi [First Name],
Hope you're well! [Mutual Connection] mentioned you're dealing with [Challenge] at [Company] and thought we should connect.
[Mutual Connection] knows we helped [Their Company] solve a similar issue last year. They suggested you might benefit from the same approach.
Without going into details here, the short version: [Client] was struggling with [Challenge] and we helped them achieve [Result] in [Timeframe].
[Mutual Connection] thought it might be relevant for [Company]'s situation.
Worth a quick conversation to see if there's a fit?
Best,
[Your Name]
P.S. [Mutual Connection] said to mention [Personal Detail/Inside Reference] - apparently you'll know what that means!