Introducing the Arista Compatible 40GBASE-ER4 QSFP+ 40km Int. Mux w/DOM SMF Duplex LC Connector TurboX | QSFP-40G-ER4-A. As an Authorised Turbo X Partner, we offer the best price and excellent service. Our dedicated team is here to find your perfect solution. Request a quote or contact us now for prompt assistance.