<b>Overview</b><br> The couplers are very well made and built tough. Allows you to connect two short ethernet cables into reasonable length without the need to buy longer ones. It is fully shielded to prevent electrical interference. Plug and play, work perfectly. <br><br><b>Specifications </b><br> Color: Black, Gray, Blue<br> Relatively sturdy and incredibly easy to use <br> Thickened PCB Board, Robust and Durable <br> These RJ45 couplers are metallic shielded <br> Supports POE applications over Ethernet patch cables<br><br> <b>Please Note </b><br> This can not use with a keystone jack. <br> It is not for a phone cable, but for an Ethernet cable. <br> They are only compatible with RJ45, NOT compatible with RJ11. <br><br> <b>Package Contents </b><br> 5 x RJ45 Coupler<br><br> <b> Note </b><br><br> <b>If you receive only 3 packs, don't worry. Please contact the seller's customer service, we will reissue the missing parts for you as soon as possible.</b><br> <b>We provide 1 year free replacement service, please contact us for any usage problems.</b>