Gotcha. Then I recommend the mc5. I use them for working out. Don't know about how durable they are, I have been working out with mine for maybe 6 months now. So far so good! Very happy with them. You might even get here custom fit inserts.
On another way more expensive note...
The ER4s though more expensive and harder to drive are repairable. The drivers can be replaced. I picked my set up in 92 and finally failed a driver about 6 months ago. I still have to send them in. I am trying to determine whether I want to replace the set for $130 or just the transducer for $85.