Statute of Frauds question

[Charles Barkley]

There is an exception that relates to merchants when the deal is for a sale of goods worth more than $500. If a writing is sent to one merchant from the other confirming the transaction, within a reasonable time, the merchant that receives the letter has 10 days to object to the transaction. If the person responds to the letter by backing out of the transaction, is the agreement not enforceable? Does it depend?

Just a little confused about this exception. Thanks for the help.