Thank you for links.
I have already looked on farnell, but it seems that I can't find suitable caps for me. It would be best if someone could draw 3d, because I don't know how, so I could just print it (my friend has 3d printer). I just need 3 of those caps, so it's not worth to pay for postal service to get it. Could someone with 3d skills draw a model for me? I know it wouldn't take much time for someone familiar with 3d cad, but for me...I don't have time to learn now. I would be very much gratefull for that.
If someone is willing to help me, please let me know, I will give dimensions.