OTOOLWORLD Watch Case Open Ball Friction Ball Watch Case Open Ball Battery Change

This review is for a OTOOLWORLD friction ball tool ordered 2026-05-16 and received 2026-05-17. I paid $6.21 including free shipping with my Prime membership. The packaging states Made in China. The ball received is a sparkly blue color, was inflated properly and included a standard needle. It's about the same size as a baseball (a little larger than a tennis ball), fits well in the hand and is easy to grip. Oddly, it even has a pleasant odor but for the same reason, I won't be repurposing to play fetch out of concern for possible toxicity. I was skeptical when I first felt it as it wasn't as sticky as I expected but less than a minute later I had the backs off of two Casio watches that have the six-slot threaded covers. I DIY basically everything but most medical and dental so there's a good chance that the friction ball and technique will be useful tool beyond watch maintenance. I presume that it'll be impossible to feel how tightly I re-install covers after replacing the batteries but I figure that as tight as is possible with the ball will be adequate.

Easily opens up watch casebacks.

The sticky ball watch back removal works quite well .. The one i received is yellow ( not my first choice of colors but who cares it's a ball ) came prefilled in it's own cardboard box , i was hesitant to purchase because of all the choices of sticky balls on amazon with mixed reviews , This one had mostly good reviews so i decided to try it anyways and for 7.99 at the time of purchase i couldn't be happier , Worked great on the first two watches that i tried it on so it's already paid for itself in my eyes . Both watches were a little hard to get open at first but within seconds they both opened right up , the ball has great gripping power and no slippage , pre inflated so there was no messing with guessing on how much air needed to be added before use . It does come with a filling needed which i put away for future use if needed but i am quite happy and impressed with it as is right out of the box ., i would def. buy again if i needed to replace . This is the one to get if you are like me and having a hard time deciding between the affordable ones and the marked up name brands that can be priced upwards of $15.00-$20.00 . This one worked perfectly at the 7.99 price so far . Hope to get many uses and years out of this sticky ball watch back removal tool , 5 stars *****

I own other case opening tools. I like the concept of having a ball opener to avoid scratches. While it did not work for all my watches, I was able to open approx. 60% of watches I worked on. For the price, it is a good tool to have.

I picked up this friction ball to help open the case back on one of my watches, but it didn’t end up working for my particular model. To be fair, it might not have been the right use case—the case back was probably too tight for a friction tool. That said, the ball feels well-made and grippy, so I can see it working fine on watches with easier-to-remove backs. Bottom line: Didn’t work for my watch, but seems like it could be useful depending on the watch and how tight the case is.

works, arrives deflated so you can pressure to your working level

The ball arrived in a plain little box with two inflation needles and no instructions. Knowing the ideal inflation pressure would have been handy, although the small size of the ball makes hitting a precise number difficult. Even quickly yanking the needle out causes a little loss of air. The ball was inflated when it arrive, albeit a little squishy. After a few unsuccessful attempts to open several watches, I added some air to firm it up somewhat. On one watch, I managed to get the back cover to rotate a tiny bit. But I couldn't get it to keep going. The problem is that this friction ball relies on you pressing it very firmly against the back of the watch and rotating. If you don't have enough pressure, the ball slips and doesn't move the cover. I found myself really exerting a lot of force to prevent slippage. Even then, the cover didn't rotate. I gave up and ordered a proper kit with a case wrench and a bunch of other watch tools. My guess is that one could open some cases with this ball, but far from all. Inflating the ball to as firm a pressure as I could manage seemed to help its contact with the watch case.

worked great, too off back of my Militaldo ML08/Rolex/Timex/Seiko's all very easily

perfect tool to add to my watch repair kit

Works great, why didn’t I buy one earlier.

all good

The product I received was fully deflated, and there is no way to inflate the ball. There are no instructions also about the same. Useless product, never buy

The item was so badly packaged that it was no longer a "ball" but a flat/collapsed contraption. The "ball" is not sticky enough to give good friction with the back case so only loosely tightened watch case backs can be opened.