When you choose a rubberquality it is important to know what substanses your profile will be in contact with. Against only normal weather, EPDM is the quality to choose.
If the profile is in contact with chemicals, neoprene (CR) quality is the right quality.
Against oil and petrol Nitril (NBR) quality is the best choice.
There is also a flameresistant quality which is frequently used offshore.
The hardness is measured in shore A (shA) on the scale of 1-100. For comparison - summertyres for cars have for example around 60o sh.A.
Spongerubber (with closed cells) is a type of rubber containing aircells. This is different from spongerubber with open cells which is not water tight. Spongerubber can also be produced with skin (extruded spongerubber). This type will be more robust against tares, rips and other external damages. Extruded spongerubber with skin has a hardness of around 60o sh.A.
Here is a list of the most common qualities: