Timesulin

I use it for my Fiasp. I have a terrible memory and can never remember if/when I have done my jab. Have been using it for 2 years now. Never had a problem with it. It just slots on to the top of your pen (swap tops around) and when you take the lid off for more than 8 seconds it resets to zero and starts counting upwards

I've found them very useful, as I also have a terrible memory and sometimes don't remember whether I've taken my insulin or not - I think this is because it becomes so habitual.
I've only broken one, when I kinda bounced it off a very solid floor - they replaced it for me.