La « merveille en un seul plongeon »

Very good

My first meeting with the One Dip Wonder did not go well, it fell onto the floor in its two parts - the coil and the magnet. It's very tiny, so this was challenging.
It attaches itself to the underside of the nib well, as it does to anything metal within reach. However, it absolutely does what it promises - the ink really does go on and on. This is particularly useful for beginners who have to keep refilling before they've managed to get into any sort of rhythm.
It is expensive, and I imagine that should you want to change to colour, especially white, cleaning it thoroughly every time could get tedious, so extras would help.
It can be rinsed well enough in situ, but like contact lenses it's advisable to put the plug in!

Arrive not tried it yet. Looking forward as have a nib that only does 1 letter at a time with ink.
Great idea. So tiny im petrified i lose it lol.
Lucky if i drop it can use a magnetic board to pick it up and find it

After using a pointed pen and found that you had to dip more often and could only do one letter at a time. The use of this saved dipping and could produce more letters therefore a better flow of writing and more uniformed.

As a reservoir, it does work well, actually. However, it IS miniscule, and rather fiddly. Sadly, after just a few uses, it pinged off across my workspace. I found the spring; the magnet, however......

Really works!

Good idea. Saves having to dip nib quite so often.