Serious Kit SPT Push To Fit Second Electrode

Written by  Aug 24, 2021

Another Serious Kit SPT Receiver

Another fantastic guest review from RubberStimmer, a long time stimmer and rubber fetishist. It builds on his last review of Serious Kit receivers suitable for both V2K and Tremblr e-stim play. You can read his first review here - Serious Kit Electro SPT And V2K Conversion Kit (Or Pimp My Tremblr).

So, it's over to RubberStimmer.

Serious Kit has a large range of SPT receivers for their iconic milker system, many of them with multi-stages. With clear sections to show what is going on and, more interestingly, bi-polar e-stim electrodes. Unfortunately for V2K and Tremblr owners, they require a Serious Kit milking system as there is no liner for the column system (you can read more about the differences and an introduction to SPT’s here).

Browsing through the options on the Serious Kit store, I spotted their push to fit second electrode designed to convert the basic Electro SPT that is typically used with either a monopole anal electrode or in triphase with a bipolar plug. One of the interesting things about using the milker receiver as a single-pole electrode is that as the power levels increase, you can lose the sensation of being milked and the perception of having a cock.

"There is an endless cycle of change from slide to sensation that allows you experience being taken to the edge of pleasure/pain and back again over and over."


This seems counterintuitive, but the brain simply does not know how to process the sensations. By turning the Electro SPT into a bipolar electrode, the sensations are focused on the cock, and you get a more conventional perception of movement but more on this later.


The push-to-fit electrode comprises a milled aluminium base and an acrylic sleeve that allows it to slide onto the SPT. There is a 4mm banana attachment point for a power box that screws into the acrylic sleeve and secures it to the base. Finally, a rubber ring is provided to prevent the two contact areas from touching. They come in the three standard SK receiver sizes and must match size.

Ringing the base are two rubber rings to secure the sleeve. The entire section can be disassembled for cleaning. At first glance, it seems simple but considerable thought has been put into the design. A slight taper has been machined into the clear section allowing the top SPT to fit firmly without damaging the liner.

Image showing the components of the second electrode
Serious Kit are well renowned for producing very well made equipment.

The bottom section has a machined channel that allows it to affix to a SK silicone harness and operate with the harness without further supports. This has some advantages but at the expense of being able to easily get in and out or reapply lube during a session.


It is not quite as simple as pushing it on. The Electro SPT uses an insulating band on the base, which is just a bit too tight. This gives you a couple of options. The first is to remove the insulation entirely, allowing a small gap between the two poles. The other way is to roll the insulation up the SPT, which allows you to control the gap between the poles. This makes the rubber insulation ring redundant.

A large gap has its advantages. Too much conductive lube can short the two poles when they are close. But, if you are on the shorter side, you may need a smaller gap. Typically the more significant the gap, the better with e-stim, but it is not essential.

After adjusting the insulating band, push the second electrode on, ensuring the powerbox connection is facing away from you and you are done.

How it feels

Image showing the second electrode fitted to the SPT receiverTremblrs and the V2K move the receiver up and down the cock in a stroking motion. Without movement, the sensation of electrostimulation covers the entire penis. As the contacts are significantly larger than loops, it feels less sharp. It is worth trying built-in routines again or stereostim files that used to feel prickly or sharp. The large contact areas make a big difference.

When the milker starts, and the V2K or tremblr moves the receiver up and down the cock in a stroking motion, the real magic happens.

The perceived sensation with estim is always focused on the pole with the smallest contact area. Normally, this does not change that much, but the contact ratio is constantly moving with the milker. The e-stim feels like it is moving with the milker, an electric stroking sensation.

At lower power, the estim adds some spice, but as the level increases, it goes from tongue like, to teeth until it feels like estim, but it is constantly changing the focus of sensation.

Lower speeds work better, allowing your brain to process better, but also it reduces the chance of pop off that can give you a lesson in the inverse proportional pain rule. The smaller the contact area, the more intense the sensation is. As the last thing contacted is likely to be the ridge of your glans, a pop-off can be eye wateringly intense.

A session with the SK and the Estim systems 2B beta firmware really showed off what is possible. There is a new feature called timewarp, which allows you to slow routines like waterfall down. At x32, the pulse builds over 10 to 20 seconds, then it remains for 10 to 20 seconds and falls away just as slowly until all you feel is the slide of the milker.

There is an endless cycle of change from slide to sensation that allows you experience being taken to the edge of pleasure/pain and back again over and over.

Unlike a monopole milker electrode, you are constantly reminded you are getting milked by a machine. It is an amazing feeling, unlike anything you are likely to have experienced.

Cleaning up

Getting fluids trapped in the second electrode is inevitable, but fortunately, the entire electrode can be stripped down for cleaning. Unscrew the power box connection point and then use a blunt wedge to gently lever the base away from the clear cylinder working around carefully.

Wash in alcohol-free cleaner like any other SK. When dry, lubricate the rubber rings with water-based lube and slide the clear sleeve down, ensuring the taper is facing up.

If you are not careful and use a clean cloth, you can get micro scratches on the clear sleeve.

These don’t affect the function, but if it worries you, they can be buffed out with headlight polish.

Image showing the fully assembled bipolar SPT receiver
Serious Kit equipment both looks and feels amazing.

The Serious Kit, push fit second electrode takes your stimming to the next level with the Tremblr or V2K, check out this review of it and grab one from @Seriouskit2. Click to Tweet

Key Features

Get it if you:

  • Want the best of both worlds, milking and estim.
  • Are an experienced player with the ecosystem of toys to make it work.
  • Are prepared to put some work in to get the best out of it
  • Find CR loops a bit sharp.

Be cautious if:

  • You are of below-average length. The receiver needs room to slide while keeping both poles in contact.

Summing up

If you are thinking about an electro SPT for your V2K or Tremblr, add it to your order. I’d go as far as to say forgo the harness and use the money to buy the push to fit second electrode. You then have a new range of sensations and so much to experiment with.

This is an unsolicited review, and the push to fit second electrode was purchased directly from Serious Kit.

Thank you RubberStimmer

I'd like to thank RubberStimmer publically for taking the time to write another fantastic review for everyone interested in this high end specialised e-stim kit. The Serious Kit range of products can really expand your horizons and your e-stim play sessions.

Where Can I Get One From?

Serious Kit

Grab one of these extremely effective pieces of equipment direct from Serious Kit for £38.

Check them out and don’t forget to tell them that Joanne says "Hi".


This review does not contain affiliate links, for more information about affiliate links check out my disclosure page.

Additional Info

  • Overall Rating: 9.0
Published in E-Stim
Joanne Summers

Sex Blogger, reviewer, dildo afficianado, kinky quimsticking, electrosex loving mum.

I've been reviewing sex toys and adult products for the last seven years and I love doing what I do. Recently I have been designing my own range of e-stim electrodes.

If you find my reviews and articles interesting please leave a comment for me on them, I love reading feedback about them. Or alternatively you could Buy Me A Coffee, wink, wink.

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