Resono Flex

£7.99 GBP

The Resono Flex is an all new Water Resistant Voice Training (WRVT) tool, with built in features to help you build a strong, healthy, resilient voice.

Package inc. 1x Resono Flex.

The Flex, explained.

Rayvox founder and Resono inventor, Oren Boder talks you through some of the features of these revolutionary vocal development tools.

Click the stories to popup the video player.

Free Your Voice With Bubbles

Water bubbling technique is a type of semi-occluded vocal tract (SOVT) exercise that involves blowing bubbles through a straw submerged in water. It is highly recommended by medical professionals as a recovery and rehabilitation intervention for intricate muscles of the voice. The technique provides bio-visual feedback from the bubbles, allowing you to see your respiratory output and identify when there's either too much or too little effort applied.

Plus, you also get alternating pressure waves from the bubbles, which creates an internal massage for your vocal muscles that helps with recovery and rehabilitation (and is great as a warmup and cool down too).

Seal the Deal with Every Note

Our uniquely designed mouthpiece creates the perfect seal for your lips, ensuring you have total control over your vocal tract oscillation, enabling the therapeutic "massage effect" for vocal muscles.

With the Resono Flex, you will literally feel your entire vocal tract (including your cheeks) oscillate / pulsate with the alternating pressure provided by the device - that means it's working to unlock the true potential of your voice.

Dive Deep into Vocal Perfection

Take the plunge with our Resono Flex's depth markings! Whether you're a shallow dipper or a deep diver, our precise indicators make it easy to find the ideal water level (and resistance) for your vocal training.

Find your sweet spot and let your voice soar.

Sterilized & Certified for Your Peace of Mind

We're committed to providing safe and reliable vocal training and rehabilitation tools. That's why each Resono Flex comes in a sterilized, individually sealed packet, ensuring maximum hygiene for your vocal training. Plus, our CE certification guarantees quality and compliance with international standards.

Sing with confidence knowing your voice is in good hands.

Sing with ease. Recover tired vocal folds. Gain vocal power without straining. Increase vocal range. Reduce vocal fatigue. Achieve faster vocal warmups. Adjust breathing for relaxation. Reduces anxiety. Sing with ease. Recover tired vocal folds. Gain vocal power without straining. Increase vocal range. Reduce vocal fatigue. Achieve faster vocal warmups. Adjust breathing for relaxation. Reduces anxiety.

Trusted by the pros

Our vocal development tools are used by Singers and Professional Voice Users from over 40 countries around the globe, as well as by Broadway, West End, and Television/Film Stars; from shows like Les Miserable, Wicked, Hamilton, Frozen, Phantom of the Opera, Chicago, and so many more!

Science in the press

"Straw phonation not only lowered the onset of normal voice, but also elevated the onset of chaotic voice, indicating a better voice economy and voice control. Moreover, the improved phonatory range demonstrated that straw phonation had the potential to prevent voice users who have high voice demand from voice fatigue and vocal damage."

Kang et al., 2018

"We think Semi-occluded Vocal Tract exercises are brill. They have a solid of research behind them and have been helping singers clinically for years. Bringing these into your daily warm up routine, or even more than once per day, will help you to warm that uncooperative little monkey into a beautifully functional instrument in half the time." 

iSingMag, 2016.

"The straw phonation exercise caused positive effects, seen upon voice self-assessment, indicating an easier and better voice upon phonation."

Costa et al., 2011.

"Narrowing the vocal tract increases air pressure above the vocal folds, keeping them slightly separated during phonation and reducing the impact collision force" 


Flex Specs.

The Resono Flex is made from FDA approved food-grade Silicone. It's flexible, durable, and designed to last. And it's dishwasher safe.

Dimensions: 300mm long, c.11mm inner diameter*, c. 20mm outer diameter*, with a 22mm built in mouth piece.

*The Resono Flex isn't perfectly round, so the inner and outer diameters are approximate.

UK Registered Design: #6266698.

Customer Reviews

Based on 8 reviews
N J Taylor
Absolutely Brilliant

This is absolutely fantastic, I have an issue with my throat and am unable to speak. I use the Resono Flex for my speech therapy sessions using water resistance to strengthen my throat muscles. Would highly recommend it's not just good for singers etc

Simon Palmer
Great piece of equipment

Great straw, love the ability to clean it. The zip up can be hard to get the knack of but once you get the hang of it it’s easy. Only slight gripe is that I wish the straw would bend easily in any direction - it only bends ‘sideways’ so the mouthpiece isn’t symmetrical in your mouth. But no biggie ☺️

Resono flex

I've only just started using the resono flex alongside my first resono straw. It's much better for water exercises. I will see how much of an improvement I notice in the coming weeks.

Helped save my voice after losing it!

I can’t live without this.. I completely lost my voice a week before a gig and this helped rehabilitate it and get it safely back and now it’s a guaranteed part of my warmup! Thankyou so much :)

Thanks so much for the kind review. We are so pleased to hear that the Flex is helping you. ❤️

Sharon D
Straws, A Singer’s Saviour 👍🏾

The Flex is a wonderful addition to my collection of SOVT straws.
I love the lip seal, the depth markings and that it is easy to clean, although zipping it back together is a learning curve I’m still on :)
A bag (with a water proof liner?) for storage and travel would have made the package complete.

Thank you for the kind words. The seal definitely gets easier with practice. We also like to use that time to make some positive vocal affirmations whist preparing the Flex for use. So I guess it's a win-win, right? Great suggestion re:waterproof travel bag too - we'll look into that!

Elizabeth Breban
Thumbs up

I love the flexibility of the straw. I love how it can be thoroughly cleaned. At first it was a little tricky putting it together but I’ve now got the hang of it. What would have been nice is if it came with a drawstring bag to keep it in and to take it out and about to gigs.

Thank you so much for the kind review, we're so glad you're enjoying it. And thank you for the suggestion re:bag - we'll explore this.

Liz Shipley
Resono flex

Great addition to the Sovt straw I already have (which I love!) and makes a huge difference to my vocal practice - I really feel my voice is so much ‘brighter’ and assured after use - my only comment would be is I find it tricky to ‘zip’ up, may get easier with practice


What a great addition to my vocal warmup. This has really made my whole warm up routine so much easier and has helped so much with previous vocal strain.

Thank you for the review. We're so glad the Flex is helping you already!