Sorry, 40G QSFP+ transeivers that operate at an industrial temperature range are currently not available, but in development. Please stay tuned. By FS on 03/17/2018

As for customized transceivers, FS.COM offers regular custom choices such as compatibility, transmission distance, operating temperature, label pattern, label colors and etc. What's more, FS.COM welcomes any inquiry for customized products and solutions for all need and specifications. By FS on 07/15/2017

Besides the price advantage we have compared to branded transceivers, FS.COM compatible transceivers also maintain the same performance and reliability. To satisfy our customers' needs of high performance, all of our transceivers are tested multiple times in mainstream original brand switches in our test center before shipped out. By FS on 06/07/2017

On one hand, the FS.COM 40G QSFP+ transceivers with LC interface are used for long-distance transmission over single mode fiber, and those with MTP/MPO interface are utilized for short distance transmission over multimode fiber. On the other hand, for the FS.COM 40G QSFP+ transceivers with LC interface, they cannot be split into 4x10G as they use 4 wavelengths on a pair of single-mode fibers and do not lend themselves to “splitting” into 4 pairs without substantial complexity to split out the wavelengths. For the FS,COM 40G QSFP+ transceivers with MTP/MPO interface, they can be used in 4x10G connectivity via an external 12-fiber parallel to 2-fiber duplex breakout cable, which connects the 40G transceiver to four 10G optical interfaces. By FS on 06/05/2017

No, the 40G QSFP+ LR4 Transceivers cannot work with 10G LR transceivers directly because the 40G QSFP+ LR4 Transceivers uses LC connectors instead of MTP/MPO connectors. If you need transceivers to have 4x10G connectivity, the #QSFP-PLR4-40G Transceivers are highly recommended. By FS on 05/25/2017

FS.COM has been maintaining huge stock level of the 40GBASE-LR4 QSFP+ transceivers in U.S. warehouse, EU warehouse and CN warehouse. As long as the products you order are all in stock, we will ship them out the same day you place your order. As for some specific products or products that have a short stock, we will keep you informed ahead of time before you place your order. By FS on 06/21/2017

Dust and contamination can accumulate on transceiver's connectors and cause problems such as reducing the optic launch power. To ensure better connection, FS.COM strongly recommends cleaning both connectors each time you disconnect and reconnect them. FS.COM High Quality One-Push Fiber Optic Pen Cleaner for 1.25mm LC/MU Connector is the best cleaning choice for 40GBASE-LR4 QSFP+ transceivers. By FS on 05/21/2017

The FS.COM 40GBASE-LR4 QSFP+ transceivers use duplex single mode fiber patch cables with LC/UPC connectors. By FS on 05/09/2017

No. Network equipment manufacturers do not require that you use only name-brand optics. In fact, when a product fault or defect occurs in the network, and the fault or defect is not attributable to the use of third-party optics, they will continue to provide support for the affected product under warranty or covered by their support program. By FS on 04/12/2017

The FS.COM 40GBASE-LR4 QSFP+ transceivers support up to 10km over single mode fibers. By FS on 03/13/2017