So you want a pair of high fidelity headphones, with the convenience of wireless Bluetooth connectivity, but donot feel like dropping three bills on them Fortunately you donot have to spend a lot of money to get high quality, A case in point is this pair of Premium Bluetooth Hi-Fi Over-the-Ear Headphones from Monoprice, These headphones use a single 50mm woofer and three 13mm tweeters in each earpiece to deliver superb sound quality across the entire musical spectrum, They feature a frequency response range of 20Hz to 20KHz and a 120dB sensitivity, so you will hear every note with clarity and as much volume as you can handle, The Bluetooth A2DP and AVRCP profiles are supported for music, allowing for wireless transmission of the audio signal as well as remote operation of the source device using the controls on the headset, The headphones have a built-in microphone and support the Bluetooth HFP and HSP profiles, so you can use them to answer and place calls from your smartphone, The Bluetooth module has a reception range of about 30-60 feet in clear air, As amazing and convenient as Bluetooth connectivity is, you still have to have a phone or music player with you or within Bluetooth range, However, with these Monoprice Headphones, you donot even need a phone or music player, Just plug a micro SD card into the card slot in the right earpiece and listen to your favorite music directly off the card, The headphones support micro SD cards up to 64GB capacity and can play mp3 and wma files, When connected to a PC or Mac through the USB interface you can see the micro SD card like any other drive on your system, allowing you to copy or delete files without the need for a separate card reader, The headphones have a built-in Lithum-polymer battery with capacity for up to 20 hours of playback and talk time and a whopping 325 hours of standby time, The battery takes about 3 hours for a full charge and is charged using the included micro USB cable, Included in the package is also a 3, 5mm AUX cable to allow the headphones to be used in wired mode, Note - The Box and manual for this item state that there are two additional cables included for a total of four cables, This is a misprint and is not the case, The only cables included are pictured, and mentioned above, We apologize for any inconvenience this may have caused you, , Drivers - 2x 50mm woofers, 6x 13mm tweeters, Bluetooth Version - Bluetooth V3, 0, Playback and Talk Time - up to 20 hours, Standby Time - up to 325 hours, Charging Time - up to 3 hours, Battery - Rechargeable Li-polymer, Woofer Impedance - 100 ohms, Tweeter Impedance - 32 ohms, Frequency Response - 20Hz - 20KHz, Sensitivity - 120dB, Operating Temperature - plus 14 - plus 122 degree F minus10 - plus 50 degree C, Dimension - 11, 3 x 7, 7 x 4 in, Item weight - 2 lb SKU: MNPR109