Telephone Line Isolation Unit “TeTech” N53 Telephone line isolation unit that can be used as the basis of a telephone music on-hold adaptor. Suitable for even the smallest business, use it to customise the on-hold music that your clients listen to. Accepts input via 3.5mm headphone socket, so it will work fine with any MP3 player. Sell as is Pick up from Birkdale, North Shore, or shipped at your cost