The POC Cortex Flow helmet is a bit different than its Cortex DH big brother. First of all, it's a single shell helmet. The exterior is made of fiberglass, and the single layer design necessitates a thicker shell. So it's a more durable shell than the carbon fiber on the Cortex DH, but it's also a heavier shell. While it takes external design cues from the Cortex DH, the single shell means the vents channel air directly into the helmet, through holes in the shell that are aligned with a like pattern in the EPP liner. In reality, it ventilates better than the DH version because of this direct flow path for fresh air. The chinguard is positioned just right so that your face is protected well and yet, you can still breathe easily on hot days as you sprint from one berm to the next. The Cortex Flow helmet is a great one and meets all the European and US safety standards. As mentioned, it vents better than its DH big brother. But the DH is a much safer helmet with its double layer construction and MIPS technology. If you've had a concussion or two, or a more serious brain injury and live for high speed excitement, do yourself a favor and go for the DH version of the Cortex Helmet. The POC Cortex Flow helmet comes in Black and White and is available in ML 55 57cm and LXL 58 60cm sizes. Read our review of the POC Cortex Flow Helmet.