Did my first TT with this and wow what a difference. Not that it came down to just the helmet as I had a few other aero advantages, but my buddy who weighs the same as me put out 30 more watts than I did and I beat him. That's huge. I also like how the wind noise you hear lets you know when you you're dropping your head and not being as aero as you could be. The visor is a little wonky and gives a bit of a walleye effect, but otherwise no complaints.
I have used Giro helmets for decades, ever since Greg Lemond's black and neon edition in TDF win vs Laurent Fignon. I've have been impressed with Giro's spherical design, which allows construction of a complete MIPS polystyrene helmet which can rotate within an outer shell helmet. Very sturdy and easy to see how it would dissipate concussive head trauma forces. Only negative is wide, dome-shape to helmet, giving a mushroom top appearance. This version is much nicer looking, lighter, and with better air flow than its predecessor. But to be honest, I exchanged it for the Meta MIPS Trenta, because it looked better, seems to have better air flow, and is what Tadej Pogacar wore in this years TDF. Tough call because I believe Vingegaard wore the Giro, and it looked pretty good on him.
I'm bald and trim what little hair I have I cut short. It's easy to get sun burn through the vents in typical helmets and sunscreen runs into your eyes. A skull cap is a must and this one works great. I previously purchased the version without the visor and purchased this one when it came on sale. Does wearing a skull cap make your head hot? Not at all, I soak it in water before a hot ride and keep it wet during the ride. The evaporation keeps my head cool, better than no cap at all. The visor extends over the top of my sunglasses and reduces glare especially in the early morning or late evening.
The DMT K1 performs exactly as billed in their description. It has great breathability and excellent feel with or without socks. The power transmission is more than enough for triathlons; however, if someone is looking to perform any sprinting I can see how the forgiveness of the upper would compromise their "all out" efforts. The fit was true to size. I have a narrow foot and there was no significant "play" in the toebox, so I cannot speak for someone with a wide foot. Overall I found it to be very good option for an individual looking for a mid to high end triathlon shoe.
