In the U.S. of A. the spec for the outer jacket to be used in walls, floors, ceilings, attics, crawl spaces and between floors is "CMR", with "R" representing ""Riser". One of CMR's properties is that the jacket's flame resistance is very high and the smoke it can produce under flame is very low. Although there's a different cable jacket rating system in EU and/or UK, it appears the intent of the jacket rating of the product you linked is similar, as it is rated "Halogen free, non-corrosive and flame retardent."
And to clarify @guykuo 's excellent tip #3 above about trimming the conductors at a 45° angle to facillitate inserting them in the RJ-45, below is an image. Although especially helpful when inserting the thicker 23 AWG conductors into the guide, it can also help when NOT using the 2 piece setup.
And lastly, with regards to his #4 tip on color code, a picture says a lot:
