Mauser SR hop up rubber

Hello,

I have a question about my mauser SR.
I need to install a new hop up rubber, but don't know which I should install.
Problem is that I have been told that it needs a special kind of hop up rubber.

Could anyone tell me what kind of hop up rubber I need to install, and what brand is the best.
Tried to find it on the internet, but no luck so far.

thx in advance

i think it takes APS rubber....80% chance...