New 7iDP Project.21 Helmet Looks Great and Provides a Good Fit for Large Heads [Review]

The 7iDP Project.21 mountain bike helmet features 21 vents, an adjustable visor, and a comfortable, protective fit.
7iDP Project.21 mountain bike helmet

The Project.21 half-shell helmet makes a brawny and stylish debut in the 7iDP helmet line-up. The limited-edition release is a part of the brand’s Holographic Limited Edition Series 1 line up, and only 500 of the helmets were made. The outer shell of the helmet has a matte black finish with minimal yet modish holographic designs that remind me of 90s holographic trading cards for an overall look that is stealthy and easy to match with any bike and kit.

7iDP Project.21 helmet specs

  • Weight: 430g (size XL/XXL)
  • Price: $229.99
  • Buy from 7iDP

Helmet features

The Project.21 helmet integrates ERT (Energy Reduction Technology) and Conehead hard foam safety tech. In addition, the Crash Release Visor is designed to release on impact to reduce rotational forces. The helmet meets CE (Europe), CPSC (North America), and AS (New Zealand) standards. The visor can be easily adjusted with one hand into an up or down position when needed. 

Illustrating how the impact and rotation reduction technologies are designed to work.

At the rear there is a ridged dial adjuster offering 53 clicks from open to fully closed. Two sets of antimicrobial liners are included, each with a different thickness for optimal fitment. A Fidlock Magnetic Closure easily snaps into place to keep the loop straps in place but can be undone with just one hand.

Fit and style

The 7iDP Project.21 rocks a sporty and “aggressive” enduro-style design. There are 21 vents, as the name implies, providing ample air flow on the trail. This may be one of the coolest half shell helmets I have tested, pun intended. Even during climbs, the helmet loves to dump hot air out the back. Plus, on hot days, the antimicrobial liner does a good job keeping sweat away from my eyes. 

I typically find myself trying all the helmets on the shelf at REI to see which brand and model fits my head more comfortably, especially when new models are released. This 7iDP Project.21 helmet cradled my head perfectly and comfortably on the first try. I was able to try a size M/L which fit a bit snug on my 61cm-circumference head, so I sized up to a size XL/XXL as usual. There are no temple pressure point pains for me and I can say this is one of the most comfortable half-shell helmets I have worn. Weighing about 430g for the XL/XXL helmet, it never felt heavy or in the way, sitting low on my head. 

The smooth-to-the-touch chin strap works perfectly and is easy to adjust while on the trail. It never undid itself after adjusting. Adjusting the visor is also pretty easy; press it down to get some sun protection and push for optimal visibility on the trail.

I had a hard time finding any gripes about this helmet, that is until I went for a night ride. Due to the size of the upper middle vents, I was only able to strap my light to the upper rear vents. I like my light to sit right in the middle of the helmet and I couldn’t set my usual light at the proper angle on the Project.21 helmet. A different helmet light that I tried worked better, but obviously this is hit or miss. Whatever happened to helmets with those GoPro-style attachments for action cameras and lights? Those need to make a comeback.

Pros and cons of the 7iDP Project.21 helmet


  • 21 Vents keep air flowing throughout
  • Comfortable and no pressure point pain
  • Padded helmet bag included


  • Some helmet lights may not strap on perfectly and securely. 

Bottom line

Ultimately, the 7iDP Project.21 has a little bit of everything I have been looking for in a half-shell helmet. The comfort and fitment are great, and the protection technology is confidence-inspiring. This is a well-rounded helmet full of features to keep up with demanding riders.