Short answer: the Bogasing M4, and it’s the cheaper one too. It ranks #24 of 135 medium speakers at $45.99; the Soundlink Flex ranks #34 at $89.00, $43 more.
Both need a mode switch to sound their best. The M4’s cons recommend its super bass mode for the most balanced sound, since the default mode runs with a boosted, harsh, thin treble. The Flex doesn’t have a mode to switch, and our notes describe it as warm with overly boosted bass that drowns out midrange detail.
The Flex’s real selling point is Bose’s durability: IP67 rated, rugged enough to survive drops from several feet, and it floats.
Buy the Bogasing M4 for the better ranking and lower price. Buy the Soundlink Flex if Bose’s ruggedness specifically matters to you.
Specifications Side By Side
| Bogasing M4 | Bose Soundlink Flex | |
|---|---|---|
| Price | $45.99 | $89.00 |
| Ranked | #24 of 134 in Medium Size Portable Bluetooth Speakers | #34 of 134 in Medium Size Portable Bluetooth Speakers |
| App | No | Yes |
| Aux Input | Yes | - |
| Bass Extension (-10dB) | 54Hz | 56Hz |
| Battery Life | 24 hours (Manufacturer specified) | 12 hours (Manufacturer specified) |
| EQ | No | No |
| IP Rating | IPX7 | IP67 |
| Bluetooth Latency | 150ms | 33ms |
| Max Volume | 99dB | 96dB |
| MicroSD Playback | Yes | - |
| Power Input | USB-C | USB-C |
| Stereo | Yes | No |
| TWS | Yes | Yes |
| Weight | 1.6 lbs / 731 g | 1.3 lbs / 589 g |
| Bluetooth Version | 5.0 | 4.2 |
| Output Power | 40W | - |
| Drivers | 52mm speaker unit | 1x 60mm full-range driver + 2x passive radiators |
| Built in Microphone | - | Yes |
| Party Mode | - | Yes (Bose Party mode) |
| Dimensions | - | 7.9" x 3.5" x 2.1" (201 x 90 x 52 mm) |
The Two Speakers In Full
Bogasing M4: $45.99 Amazon
Pros: Use super bass mode for the most balanced sound
Cons: A bit harsh and thin sounding. Default mode has a boosted treble.
| App | No |
|---|---|
| Aux Input | Yes |
| Bass Extension (-10dB) | 54Hz |
| Battery Life | 24 hours (Manufacturer specified) |
| Bluetooth Latency | 150ms |
| Bluetooth Version | 5.0 |
| Drivers | 52mm speaker unit |
| EQ | No |
| IP Rating | IPX7 |
| Max Volume | 99dB |
| MicroSD Playback | Yes |
| Output Power | 40W |
| Power Input | USB-C |
| Stereo | Yes |
| TWS | Yes |
| Weight | 1.6 lbs / 731 g |
- Reviews, Comparisons and Sound Samples
- Alan Ross Reviews: Bogasing M4 Review - vs JBL Charge 5 & Motion Plus - a new contender?
- Alan Ross Reviews: Bose Soundlink Flex vs Soundcore Boost vs Bogasing M4 - cheap or Bose?
- Alan Ross Reviews: Bogasing M4 or Soundcore Boost or Maxsound Plus for $50 champion?? 🤷♀️
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Bose Soundlink Flex: $89.00 Amazon
Pros: IP67 rated; rugged enough to survive drops from several feet and floats. Around 12 hours of battery at moderate volume.
Cons: Not stereo. Warm sounding with overly boosted bass which drowns out midrange detail
| App | Yes |
|---|---|
| Bass Extension (-10dB) | 56Hz |
| Battery Life | 12 hours (Manufacturer specified) |
| Bluetooth Latency | 33ms |
| Bluetooth Version | 4.2 |
| Built in Microphone | Yes |
| Dimensions | 7.9" x 3.5" x 2.1" (201 x 90 x 52 mm) |
| Drivers | 1x 60mm full-range driver + 2x passive radiators |
| EQ | No |
| IP Rating | IP67 |
| Max Volume | 96dB |
| Party Mode | Yes (Bose Party mode) |
| Power Input | USB-C |
| Stereo | No |
| TWS | Yes |
| Weight | 1.3 lbs / 589 g |
- Reviews, Comparisons and Sound Samples
- Joy & Oluv’Sone: Bose Soundlink Flex 2nd gen vs Flex
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- Jay’s Straight Up Reviews & More: Tribit Stormbox Flow vs Soundcore Motion 300 (LDAC) 😵 Budget Bose Soundlink Flex “Inspired” Speakers
- Oluv Patreon: Soundcore Motion 300 = Bose Soundlink Flex = Earfun UBoom L?
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- Jay’s Straight Up Reviews & More: Tribit Stormbox Flow vs Soundcore Motion 300 (LDAC) 😵 Budget Bose Soundlink Flex “Inspired” Speakers
- Patricio Benadon: Bose SoundLink Flex vs. Mini 2 SE. Music audio quality sound test. Listen 4 different genres!
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- Danny Pops: BEST Bose Speaker?? Bose Soundlink Flex vs micro, Color II, and revolve +
- Alan Ross Reviews: Bose Soundlink Flex vs Minirig MK3 and Marshall Emberton - best bluetooth speaker?
- Joy & Oluv’Sone: JBL, Bose, B&O, Sonos, Earfun, SoundCore… which portable speaker sounds best?
- Alan Ross - The Anti Shill!: Small speaker, mighty sound, The Flex gen 2 shatters physics!
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- Links
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Product prices and availability were last checked August 9, 2026 at 6:57 AM UTC and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.