Shocked at the negative reviews as this works great with my tens unit. Make sure the battery is charged and you won't have any problems with the strength.

Only complaint I have is that it's a bit too small, wish it was a bit larger as it's not too much bigger than a baby pacifier. You really have to "clamp down" to make sure it stays in place which in itself gives a good workout.
If you insert it too far you won't feel anything because it only works when touching the actual muscle.
Can definitely feel it working, can't wait to see the results after using it for awhile.

I bought the iStim TENS device and this probe to address my annoying stress incontinence. I wanted to get the same brand device/probe and the iStim device had good reviews. Unlike the Yarlap and a few other pelvic floor strengthening devices on Amazon, the iStim device doesn't have programs specifically for that issue and no settings for it are in the manual so I was on my own.
A few tips:
- I found out the hard way that the knob at the top of the iStim doesn't just turn the chosen channel (there are two) off and on, it also changes the intensity, so be careful when you increase/crank it up. This is confusing, as inside the little door on the device there are not just buttons to choose from among the many the modes/programs (see iStim reviews.....remember, no programs are specific pelvic floor/probe settings), but also increase/decrease arrows for the pulse rate and width. So, I thought that was the only "intensity" control.
- If you want to feel what is going to be going on inside you and make sure the probe/device are working, you can touch the metal part of the probe with a wet hand...mini shock! So you don't want to be inserting it when it is revved up as you will feel that all along the delicate skin of the route into the placement area. Insert it first and then select settings that work for you. I find 120 to start a good level, and 30Hz. (Remember I am winging it, so choose your own comfort/effectiveness level.) I used the modulation mode.
- I can feel the pulses more, and more pleasantly, when it is in the lower pelvic muscle area (isn't our g-spot around there? It's not THAT pleasurable anyway, despite what some loving husbands say in reviews re their wives' results). If you insert it deeper you can still feel it is working and I think that is an area I need to tone up too so I have been doing 20 minutes in each area.
I do feel quite a difference in the tone of the muscles and my ability to tighten them when my annoying allergy-related cough comes on. The Yarlap has wonderful reviews and the benefit of having select programs for mixed, stress and urge incontinence but I am not able to afford it ($269 on their website with their current $30 coupon, and free shipping and 60 day return policy). This seems to be a good alternative for $60 (for iStim and probe.)
Side note: in some research I found that people treat bladder issues by using the TENS or EMS device without a probe, by placing the gel pads in the sacral area. I dunno....doesn't seem like that would be as effective as the contractions created with the probe but I might do that too since the pads and lead wires came with the iStim.
Speaking of which, I also have neck pain from degenerative disk disease (thanks, aging, the gift that keeps on giving!). Last night I tried the gel pads with the iStim and it did help. Unlike the you're on your own probe usage, the manual has lots of info on where to place pads on your body and what levels to use. It's nice to have one device (small and easy to take with you when you travel) that handles two important issues.
I would recommend the iStim AND the iStim probe. I would have given the probe 5 stars if it had instructions re which levels/modes/programs to use for pelvic floor strengthening.

This is one of three different styles of internal electrodes made by iStim. Each one for a specific purpose. This one's claim to fame is that it's made NOT to disappear and create problems requiring help.

The only internal option for men wanting to exercise their PC muscles or strengthen their pelvic floor. Women have more options. External electrode sticky-pads are also an option, but not as targeted or easy to use IMHO.

Unfortunately, one very important detail is missing from the instructions included with any of the internal probes: setting to use on your EMS machine. Sure, you can "trial and error", but something definitive from the manufacturer would do a lot to bolster confidence and overcome hesitance to use the device. As the instructions that come with iStim's EMS/TENS units are otherwise quite specific, the lack of any mention for setting for the internal probes is a glaring omission.

I also didn't find any such guidance in their web site. Too bad. An obvious omission.

I placed it next to a toothbrush because that's more of a standard over my hand.

Ok many reviews I read said that the kneading was the best setting for the TENS unit, but I found that too constant and annoying. If you don't like a little pain, stick with the kneading. I use it with the depth setting at its deepest setting.

If you maybe have a tiny pain kink, use the acu setting. It's either acupuncture or acupressure but it goes through a cycle. It starts out fine, just a buzzy feeling but then it goes into an almost pin poke sensation. It truly makes you flex the muscle it's poking lol
Then when you think you just can't take one more poke, that fades away to an amazing buzzy/contraction.

The complete tens unit cycle wants to run for I think 60-70 minutes. With each of the ACU cycles being maybe 3-5 minutes? I didn't time it, but I should have. I did not make it through the full 60-70 minute cycle.
Each cycle of the ACU setting seemed to "wake up" more and more muscles as it went.
My core flex was all the way out to my ribs when I finally threw in the towel. I was a giant pile of sweat like I had just completed a hard workout.

Also - I have seen men comment on how great it feels on the prostate, I don't have one of those- but the general muscle contractions in that general area felt very nice. I was for sure chasing an orgasm by time I finished my first use.

I used it again this weekend so I think that was two weeks between. This time it still flexed my core and when I got up and moved around after I could really feel it in my core. I assume as my muscles get stronger it's going to feel different each time.

It's amazing what it has done for my core! I'm 53, post menopausal and had a potato 🥔 shaped body a couple months ago. Now I'm getting my waist back and when I sit down my belly is the same as when I stand!

Affordable and works well. As a physical therapist, I buy these often for my clinic for my clients to purchase. I have not had one complaint yet.