営業担当者は対応してくれて、すぐに不良品を交換しました。そして送料無料です。

Quality products which have worked without problems. We've used 8 different products, all SFPs and QSFP+s, and have no issues.

They did everything they said they would do. The transceiver came on promised date and it worked as expected. I am well pleased with this company and have recommended it to others.