Halo TWIN RAIL 700x38cAll New Trail and Street tyre.Utilises 2 central rails (ridges) for reduced buzz on hard surfaces, but features drive 'sleepers' between the 'rails' to give traction on loose surfaces (Halo patent pending). Also features overlapping low profile studs to avoid lateral flex during hard cornering, and so provide positive steering. Multi use pressures allow this one tyre to perform in almost all conditions... both on road and off road. Built-in Puncture Protection System reduces flats.Directional, universal front or rear tread. knurled ground contact points.High quality lightweight carcass.Built-in Puncture Protection SystemBlack sidewall.Road.cc review - 2009. 4/5 Starshttp://road.cc/content/review/4680-halo-courier-twin-rail-tyreUltra Endurance racer Paul Errington uses Halo Twin Rail tyres and Halo wheels and has this to say about them: "I use Halo tyres and wheels as just starting an ultra endurance race is not enough .. I want to finish ! Among the many considerations when tackling long distance events the selection of the equipment you are going to use is at the top as bad choices make for bad races. The Halo product is so versatile my bike set up for the cobbles of Belgium to the gravel roads of Iowa was identical ... no problems were had and no doubts were ever raised."Check out Paul's Blog: http://shoestring-racing.blogspot.co.uk/Product Video: https://youtu.be/o6X5PPct0Qc