Filter provides uninterrupted DSL service and crystal clear conversations. Sharing a DSL connection with analog telephones may cause interference. 2 Wire DSL filters eliminate all interference between DSL line and analog telephone lines. The result is clear, clean lines for your telephones, fax machines, answering machines, caller ID and analog modems. All 2 Wire DSL filters also ensure that telephones never cause the DSL modem to adjust to the charging conditions of your DSL connection (Called retraining), which could hinder your internet access speeds. FCC approved. Male to Female RJ11. Overall length of 7”. Color is off-white.