BALL RESCUER: Tennis Ball Pressurizer – Converts Compatible Tennis Ball Container into a 30 psi Ball Pressurizer & Extends Ball Life (Pump & Container not Included in Standard and Standard Plus)

Works great. I think it even makes the balls firmer than factory. It's allowed me to keep playing with the balls for weeks. Worth the cost if you play a lot and don't require new balls every time. I wish they sold long tubes for it.

This product is excellent for maintaining the pressure of new balls. Does exactly what it is supposed to do. However, it does not add pressure back into already-flat balls. I assumed it would, but it doesn't, and can't. The reason is that when you put a flat ball in, and pressurize the can, the flat ball will squish--actually dent--until the pressure inside the ball is the same as the pressure in the can. If the ball were rigid, then air would go into the ball, but the ball of course isn't rigid so higher pressure air outside the ball just squishes it. Oh well. It's still quite useful to have it maintain the pressure of the balls. Note that you need a Penn or Dunlop ball can. Wilson and Babolat ball cans don't fit.

This only fits with some tennis ball canisters. It works fine with the ones it fits, but it’s a bit annoying to have to go out of our way to find tennis balls that specifically have the right size canister based on the manufacturing country. For the price, I would probably prefer to just purchase the full canister-sized pressure savers instead.

great product, saved me a lot of balls, great invesment.

For decades I used the classic yellow and white ball savers that hold pressure up to 14 psi. If that thing lost pressure you wouldn;t know and the balls were never really re-juvinated. The thing I like about this ball rescuer are: 1. Creates pressure up to 30 psi and holds the pressure for a very long time. Had it for a week and still no loss of pressure. 2. Easy to tell if it loses pressure and can be topped off or fixed with cleaning and lubricating the o-ring just like other ball savers. The way the mechanism works its much easier to keep dust and debris away from the part that needs to hold pressure. 3. Re-uses cans. I use Penn balls and the Penn cans work great with this.

Once you find the right container (which took some time), the product works. I bumped it down to three stars due to the fact that it is difficult to find the right container. It seems like ball manufacturers have started to change the diameter of their ball containers to prevent use of these products.

Suelo jugar con 4 pelotas y no conseguí envases de 4 pelotas que encajaran de manera correcta en estos presurizadores, así que decidí usar 2 de cualquier marca para adaptarlo, use uno de marca Wilson y otro marca Yonex, ambos de 4 pelotas, lo único que hice fue calentar ambos lo suficiente en la parte superior con una pistola de calor y despues de unos pocos minutos al estar un poco blando el plástico lo presione con el presurizador y tomo la forma exacta encajando de manera formidable, ya he adaptado varias marcas, recomiendo hacerlo si el envase que les gusta no se ajusta al cierre del presurizador, dejo un par de videos para mostrar el resultado. Nota adicional, probando otros envases me di cuenta que el tubo de pelota de marca "Dunlop Fort clay court" de 4 pelotas y cuyo envase es de metal, encaja perfectamente y mantiene la presión desde principio a fin, el único detalle es que no es transparente asi que no se puede observar la condición de las pelotas, es bueno recordar que a lo largo del uso perderá la capacidad de poder recuperar la presión y si se carga con los 30 PSI las pelotas pueden hundirse si ya están muy blandas.

Difficult to open after closing, looks like impossible to open. I used a power compressor so I think the rubber gauge is already broken, it is air leaking. Use hand air pump only. I edited my review. I finally figured out how to open it and I bought a hand pump.