This is my review for the M1 Wireless Bluetooth 4.1, Stereo HiFi Magnetic Headphones, c/w built-in mic, for sports workouts Sold by EasyLinkEU and fulfilled by Amazon.
The item arrived quickly in a cardboard book-wrap, within was the retail packaging. All of which was recyclable.

So, what do you get? 

Package Includes.
A set of LinkWitz M1 Headphone
The User Manual
A Charging Cable
2 extra pairs of Ear Tips
12 Month satisfaction warranty
Product Specifications.
Headset Weight 24 Grams
Bluetooth Version: 4.1
Frequency: 20Hz-20KHz
Battery Capacity: 150mAh
Talk Time: 11hrs
Play Time: 10hrs
Standby Time: 320hrs

The Technology.

Bluetooth 4.1

The Bluetooth SIG (Special Interest Group), released Bluetooth 4.1 as an incremental software update to Bluetooth 4.0 on 4 December 2013. This update incorporated the Bluetooth Core Specification Addenda (CSA 1, 2, 3 & 4) in this, new features were added that improve consumer usability. Including increased co-existence support for LTE and bulk data exchange rates.

The Name Bluetooth came from the 10th-century, second king of Denmark, King Harald Bluetooth; who was famous for uniting Scandinavia just as we intended to unite the PC and cellular industries with a short-range wireless link. Copyright © 2017 IDG Communications, Inc.

Now to the Sound Quality.

Well, i really put them through their paces. Using a Benchmark test and some of my favourite listening tracks. How did they perform, well let’s see.

Please Note:- I am 57 and peoples hearing change as they get older, so this is just the results that i found with my delicate ears. The Headphones were tested with flat equalisation. Tests performed using 24-bit/96kHz FLAC on a FiiO X3 2nd edition. 

Benchmark Test

Frequency response stated:- 20Hz – 20kHz.  I found heard frequencies of 20Hz – 13kHz

Spectral Flatness:- Did the Headphones perform with equal volume across a full Spectral frequency sweep. The sound was centred across the full spectrum until the top end where it wavered a slightly.

Dynamic Range:- 78 dBFS (decibels below full scale).

Quality Test:- (Bass Shaker) The sweeping tone sounded clear across all frequencies. There was no parasitic buzzing or rattling, sometimes associated with lower priced headphones.

Driver Matching:- (All frequencies swept from 10 Hz up to 10 kHz. at exactly the same sound levels in both earphones) The tone mostly held it’s central position until the top end of the spectrum.

Correctly wired:- (left plays on left and right on right) perfect.

Polarity Preserved:- (wired in phase) Yes it is.

Binaural Test:- (a knock to a wooden door, first right then left) The Knocks were well defined and very lifelike.

Listening Test.

Last but not least, I always listen to my favourite music. How does it sound? I know how it usually sounds. (Tracks used for this were as follows)

Izzy Bizu – Talking to you. Adele – Hello. Michael Jackson – She’s out of my life. 10cc – I’m not in love. Michael Jackson – Don’t stop ’til you get enough. A-ha -Hunting high and low. Gwen Guthrie – Ain’t nothin’ going on but the rent. Al Jarreau – Where in this love together. Iona – Here i stand. Patti Austin/Quincy Jones – “Betcha’ Wouldn’t Hurt Me”. Phil Collins – In the air tonight. Pink Floyd – Shine On You Crazy Diamond. Monique Miller – At last. Gino Vannelli – Black and Blue.

What are they like to use?

I found this item quick and easy to pair, with all of our bluetooth enabled devices. ie, phones, tablets, music players etc. We found the connection to devices was stable and not easily disrupted. These are perfect for wearing while jogging, running, cycling or any other kind of exercises, but the seller does fail to mention what the IP Rating is (how waterproof they are). The magnetic earbuds allow you to attach the two headphones together when not in use. I found this very convenient for carrying them about my neck, the flexible collar allows you to pack it into half the space headphones would normally take, so they would easily fit it into your pocket whilst on the go.
The in-built 150mAh high-performance rechargeable battery allows a talk time up to 11 hours and a play time up to 10 per charge. The Maximum standby time is stated as 320 hrs.

What do we think of this item?

When we unpacked the headphones I thought they looked very flimsy and really didn’t expect a lot from them. How wrong I was, I am glad to say.
As soon as the music started to play I was in ore of these headphones, the bass is deep and rich, the mid tones are smooth and well balanced and the treble is crisp, Altogether the soundstage is quite wide and well defined. All in all the musical experience is one you won’t forget for a while.
Some of my favourite music has very special memories for me so to hear it sound so beautiful brought some memories flooding back.

In Conclusion.

This is a great product for a very reasonable price, great quality, great sound, great value. I found these headphones to be as good if not better than some of the well appointed more expensive brands. I can fully recommend this product without hesitation. It gets a 5 out of 5 from me.