Shure SRH840 is a model of over ear headphones with closed back cups of a professional American audio brand. It comes with a wired connection.
The impedance of Shure SRH840 states 44 Ohm. It has a pretty wide field of frequencies: 5Hz-25KHz. The headphones reproduce a pretty loud sound with sensitivity of 102 dB. The Shure SRH840 specs make it a decent choice of Hi-Fi headphones.
I find the sound of Shure SRH840 flat and harmonious for both critical and casual listening. I like its deep bass that sounds engaging and suits most tracks. The mids are neutral and highs are less emphasized. As I have expected, the soundstage is not spacious, because of the closed cups.
There is only one option to connect the headphones, with a wire. Fortunately, it is detachable and may be changed and it is also safer if it tangles. The cable length is 3 m/9.8 ft.
To tell you the truth, it seems to me plasticky and cheap-looking. Still they are comfortable to wear with amply padded headband and ear cushions. They look very bulky and do not fold for a smaller size. I managed to adjust the headband for my head size to fit perfectly. It is not the lightest version of over ear headphones with the weight of 372 g/13.1 oz.