Patented Callus Builder & Finger Strengthener – Resistance Finger Exerciser for Guitar, Bass & Violin – Guitar Finger Trainer & Grip Strength Tool – Ideal Guitar & Bass Accessories (Tensions: RED=8-Lbs; BLACK=15-Lbs)

Easy to use! Already feeling the finger tips getting the work out! After two days Great product 👌

I’m a professional orchestral musician and I bought this to keep my calluses up when I’m away from my instrument. After a couple of weeks of using this my calluses were bigger than ever and my hand strength is also up. The black strengthener is probably more intense than a guitarist would ever need, but this device perfect for working professionals who play everyday.

I recently started up playing guitar again after taking a hiatus for a couple years. Unfortunately, the calluses I built up long ago faded away. I bought this set of callus builders to see if I could accelerate the process of building up callus. I debated buying only the 15 lb. device but opted to pay a little more and buy the set of both the 8 lb. and 15 lb. devices. I’m glad I did. Both weights will strengthen your fingers and help build callus, but my 70 year old fingers found the lighter one easier to use, at least until I can build up more finger strength. But both are definitely helpful, and they’re easy to use while watching TV. My only complaint is these devices are somewhat small. I have to bunch my fingers up a little bit to fit all 4 fingertips on the device to build callus. It would have been better if these were about 1/4 inch wider. Overall, I’m pleased with these callus builders. They’re kind of expensive for glorified potato chip bag clips, but they work as advertised, and I’m sure I’ll get a lot of use out of them.

Seems to help maintain callus as described and is comfortable to hold. Useful to fidget with while I'm working on other things. Makes a slight creak as the plastic hinge wears. And the magnet on the back can't even hold it's own weight on a metal surface so that part is useless. Has not broken yet but curious how long it will last. For 20 bucks I expected a higher build quality.

after using for a couple of weeks, i notice a huge improvement while playing the bass. im not sure if the strengthening is doing much, but it for sure helps with building up callouses

This is my 2ed one and booth springs broke in about 3 months . Im not buying another one. Will ask for new spring.

I haven't experience any issues like some other reviews have talked about with the unit breaking after some days of using it. I've been using this mostly daily for almost a month now and it works very well. Plastic and rubber(or maybe silicone?) parts look and feel thick and sturdy. Maybe it would cause an issue if you squeeze very hard and fast over and over, but that's not how you should use this product anyway. The goal isnt to squeeze as hard as you can. I press hard but not too hard to where it's painful, slowly do a few reps squeezing the clip about halfway, causing deep imprints on my finger tips. Then i move my fingers left, right, up, down while i hold down on a single line. Which essentially just tugs the skin on your finger tips in every direction, causing your skin to want to callus even more. Honestly i think pulling the skin causes callus more than just pressure on an area. Haven't tried the magnet but it seems firmly attached by a blot of glue. The magnet does move around a tad so if you used the magnet on a daily basis i can see maybe eventually it would fall off and you would have to re-glue it. Really not a big deal. I'm honestly not sure why this isn't more of a common tool you see around. Searching Amazon this one is really the only one that pops up. Definitely works though.

Love this, definitely works to help create calluses on my left hand to have proper pressure on the guitar strings.

Excellent little unit for building up callous’s on your fingers. I’ve played 50+ years and I wish I knew about this back then. Not too cheap but great quality and should last a lifetime

Hatte mir den Zeigefinger gebrochen, 4 Monate fast nicht mehr Gitarre gespielt. Aber nun seit einer Woche trainiere ich mit dem Teil, die Haut wird stark und auch der Finger wird wieder stark.Bin sehr glücklich.

グリップ留めに使ってます。指のギター弦用トレーナーなんだけど、それはどうかなぁ。

I was a little a sceptical about this product building the calluses. But I thought as nothing more than a finger strengthening gadget it'll be good. However it's done wonders for the calluses. I can now squeeze it with my finger tips with no pain what so ever which clearly indicates they are there and have formed nicely, and in a short period of time, less than a week I'd say.

タイトルは、おそらく誤解されてこれを買ってしまう方もしくは使ってしまう方向けへのメッセージです いくつかのレビューでばねの耐久力について言及されていますが、ハンドグリッパーのように開け閉めして使えばすぐ壊れるようなバネです。このツールの主な目的はカルス（硬質化した指先）の構築であって、指先に弦の形で圧がかかれば十分です。言い換えればバネなしで、この弦の形に成形されているプラスチックパーツを握りしめていれば良いはずですね。ただそれだと持ちにくいので、クリップの歯が浮くか浮かないかくらいの力で押していれば十分だと思います。 Fenderロゴは許諾を得ていない疑惑はありつつも見た目もいいし満足しています