They are tapered and have a stainless retaining clip at the top. Supposed to be superior to the dunlops. As to whether they last longer god knows but they have a 5 year guarantee versus 2 years for dunlops
The tapered feature and the stainless clip doesn't seem to give me any confidence that its less likely to leak air, although the 5 yr guarantee does appeal to me.
But, when it comes to value for money, it doesn't work if I can get 4 yrs out of the Dunlops, which I would expect them to manage.
I can see this new hobby is going to need a big calculator!
Thanks @alanlucas for some great information.